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AVR-USB Driver Software License Agreement
Version 2006-07-24
THIS LICENSE AGREEMENT GRANTS YOU CERTAIN RIGHTS IN A SOFTWARE. YOU CAN
ENTER INTO THIS AGREEMENT AND ACQUIRE THE RIGHTS OUTLINED BELOW BY PAYING
THE AMOUNT ACCORDING TO SECTION 4 ("PAYMENT") TO OBJECTIVE DEVELOPMENT.
1 DEFINITIONS
1.1 "OBJECTIVE DEVELOPMENT" shall mean OBJECTIVE DEVELOPMENT Software GmbH,
Grosse Schiffgasse 1A/7, 1020 Wien, AUSTRIA.
1.2 "You" shall mean the Licensee.
1.3 "AVR-USB" shall mean the firmware-only USB device implementation for
Atmel AVR microcontrollers distributed by OBJECTIVE DEVELOPMENT and
consisting of the files usbdrv.c, usbdrv.h, usbdrvasm.S, oddebug.c,
oddebug.h, usbdrvasm.asm, iarcompat.h and usbconfig-prototype.h.
2 LICENSE GRANTS
2.1 Source Code. OBJECTIVE DEVELOPMENT shall furnish you with the source
code of AVR-USB.
2.2 Distribution and Use. OBJECTIVE DEVELOPMENT grants you the
non-exclusive right to use and distribute AVR-USB with your hardware
product(s), restricted by the limitations in section 3 below.
2.3 Modifications. OBJECTIVE DEVELOPMENT grants you the right to modify
your copy of AVR-USB according to your needs.
2.4 USB IDs. OBJECTIVE DEVELOPMENT grants you the exclusive rights to use
USB Product ID(s) sent to you in e-mail after receiving your payment in
conjunction with USB Vendor ID 5824. OBJECTIVE DEVELOPMENT has acquired an
exclusive license for this pair of USB identifiers from Wouter van Ooijen
(www.voti.nl), who has licensed the VID from the USB Implementers Forum,
Inc. (www.usb.org).
3 LICENSE RESTRICTIONS
3.1 Number of Units. Only one of the following three definitions is
applicable. Which one is determined by the amount you pay to OBJECTIVE
DEVELOPMENT, see section 4 ("Payment") below.
Hobby License: You may use AVR-USB according to section 2 above in no more
than 5 hardware units. These units must not be sold for profit.
Entry Level License: You may use AVR-USB according to section 2 above in no
more than 150 hardware units.
Professional License: You may use AVR-USB according to section 2 above in
any number of hardware units, except for large scale production ("unlimited
fair use"). Quantities below 10,000 units are not considered large scale
production. If your reach quantities which are obviously large scale
production, you must pay a license fee of 0.10 EUR per unit for all units
above 10,000.
3.2 Rental. You may not rent, lease, or lend AVR-USB or otherwise encumber
any copy of AVR-USB, or any of the rights granted herein.
3.3 Transfer. You may not transfer your rights under this Agreement to
another party without OBJECTIVE DEVELOPMENT's prior written consent. If
such consent is obtained, you may permanently transfer this License to
another party. The recipient of such transfer must agree to all terms and
conditions of this Agreement.
3.4 Reservation of Rights. OBJECTIVE DEVELOPMENT retains all rights not
expressly granted.
3.5 Non-Exclusive Rights. Your license rights under this Agreement are
non-exclusive.
3.6 Third Party Rights. This Agreement cannot grant you rights controlled
by third parties. In particular, you are not allowed to use the USB logo or
other trademarks owned by the USB Implementers Forum, Inc. without their
consent. Since such consent depends on USB certification, it should be
noted that AVR-USB will not pass certification because it does not
implement checksum verification and the microcontroller ports do not meet
the electrical specifications.
4 PAYMENT
The payment amount depends on the variation of this agreement (according to
section 3.1) into which you want to enter. Concrete prices are listed on
OBJECTIVE DEVELOPMENT's web site, usually at
http://www.obdev.at/avrusb/license.html. You agree to pay the amount listed
there to OBJECTIVE DEVELOPMENT or OBJECTIVE DEVELOPMENT's payment processor
or reseller.
5 COPYRIGHT AND OWNERSHIP
AVR-USB is protected by copyright laws and international copyright
treaties, as well as other intellectual property laws and treaties. AVR-USB
is licensed, not sold.
6 TERM AND TERMINATION
6.1 Term. This Agreement shall continue indefinitely. However, OBJECTIVE
DEVELOPMENT may terminate this Agreement and revoke the granted license and
USB-IDs if you fail to comply with any of its terms and conditions.
6.2 Survival of Terms. All provisions regarding secrecy, confidentiality
and limitation of liability shall survive termination of this agreement.
7 DISCLAIMER OF WARRANTY AND LIABILITY
LIMITED WARRANTY. AVR-USB IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY
KIND. TO THE MAXIMUM EXTENT PERMITTED BY APPLICABLE LAW, OBJECTIVE
DEVELOPMENT AND ITS SUPPLIERS HEREBY DISCLAIM ALL WARRANTIES, EITHER
EXPRESSED OR IMPLIED, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE, TITLE, AND
NON-INFRINGEMENT, WITH REGARD TO AVR-USB, AND THE PROVISION OF OR FAILURE
TO PROVIDE SUPPORT SERVICES. THIS LIMITED WARRANTY GIVES YOU SPECIFIC LEGAL
RIGHTS. YOU MAY HAVE OTHERS, WHICH VARY FROM STATE/JURISDICTION TO
STATE/JURISDICTION.
LIMITATION OF LIABILITY. TO THE MAXIMUM EXTENT PERMITTED BY APPLICABLE LAW,
IN NO EVENT SHALL OBJECTIVE DEVELOPMENT OR ITS SUPPLIERS BE LIABLE FOR ANY
SPECIAL, INCIDENTAL, INDIRECT, OR CONSEQUENTIAL DAMAGES WHATSOEVER
(INCLUDING, WITHOUT LIMITATION, DAMAGES FOR LOSS OF BUSINESS PROFITS,
BUSINESS INTERRUPTION, LOSS OF BUSINESS INFORMATION, OR ANY OTHER PECUNIARY
LOSS) ARISING OUT OF THE USE OF OR INABILITY TO USE AVR-USB OR THE
PROVISION OF OR FAILURE TO PROVIDE SUPPORT SERVICES, EVEN IF OBJECTIVE
DEVELOPMENT HAS BEEN ADVISED OF THE POSSIBILITY OF SUCH DAMAGES. IN ANY
CASE, OBJECTIVE DEVELOPMENT'S ENTIRE LIABILITY UNDER ANY PROVISION OF THIS
AGREEMENT SHALL BE LIMITED TO THE AMOUNT ACTUALLY PAID BY YOU FOR AVR-USB.
8 MISCELLANEOUS TERMS
8.1 Marketing. OBJECTIVE DEVELOPMENT has the right to mention for marketing
purposes that you entered into this agreement.
8.2 Entire Agreement. This document represents the entire agreement between
OBJECTIVE DEVELOPMENT and you. It may only be modified in writing signed by
an authorized representative of both, OBJECTIVE DEVELOPMENT and you.
8.3 Severability. In case a provision of these terms and conditions should
be or become partly or entirely invalid, ineffective, or not executable,
the validity of all other provisions shall not be affected.
8.4 Applicable Law. This agreement is governed by the laws of the Republic
of Austria.
8.5 Responsible Courts. The responsible courts in Vienna/Austria will have
exclusive jurisdiction regarding all disputes in connection with this
agreement.

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/* Name: usbconfig.h
* Project: AVR USB driver
* Author: Christian Starkjohann
* Creation Date: 2005-04-01
* Tabsize: 4
* Copyright: (c) 2005 by OBJECTIVE DEVELOPMENT Software GmbH
* License: GNU GPL v2 (see License.txt) or proprietary (CommercialLicense.txt)
* This Revision: $Id: usbconfig-prototype.h,v 1.1 2013-04-25 02:18:15 cvs Exp $
*/
#ifndef __usbconfig_h_included__
#define __usbconfig_h_included__
/*
General Description:
This file is an example configuration (with inline documentation) for the USB
driver. It configures AVR-USB for an ATMega8 with USB D+ connected to Port D
bit 2 (which is also hardware interrupt 0) and USB D- to Port D bit 0. You may
wire the lines to any other port, as long as D+ is also wired to INT0.
To create your own usbconfig.h file, copy this file to the directory
containing "usbdrv" (that is your project firmware source directory) and
rename it to "usbconfig.h". Then edit it accordingly.
*/
/* ---------------------------- Hardware Config ---------------------------- */
#define USB_CFG_IOPORTNAME D
/* This is the port where the USB bus is connected. When you configure it to
* "B", the registers PORTB, PINB and DDRB will be used.
*/
#define USB_CFG_DMINUS_BIT 0
/* This is the bit number in USB_CFG_IOPORT where the USB D- line is connected.
* This may be any bit in the port.
*/
#define USB_CFG_DPLUS_BIT 2
/* This is the bit number in USB_CFG_IOPORT where the USB D+ line is connected.
* This may be any bit in the port. Please note that D+ must also be connected
* to interrupt pin INT0!
*/
/* #define USB_CFG_CLOCK_KHZ (F_CPU/1000) */
/* Clock rate of the AVR in MHz. Legal values are 12000, 15000, 16000 or 16500.
* The 16.5 MHz version of the code requires no crystal, it tolerates +/- 1%
* deviation from the nominal frequency. All other rates require a precision
* of 2000 ppm and thus a crystal!
* Default if not specified: 12 MHz
*/
/* ----------------------- Optional Hardware Config ------------------------ */
/* #define USB_CFG_PULLUP_IOPORTNAME D */
/* If you connect the 1.5k pullup resistor from D- to a port pin instead of
* V+, you can connect and disconnect the device from firmware by calling
* the macros usbDeviceConnect() and usbDeviceDisconnect() (see usbdrv.h).
* This constant defines the port on which the pullup resistor is connected.
*/
/* #define USB_CFG_PULLUP_BIT 4 */
/* This constant defines the bit number in USB_CFG_PULLUP_IOPORT (defined
* above) where the 1.5k pullup resistor is connected. See description
* above for details.
*/
/* --------------------------- Functional Range ---------------------------- */
#define USB_CFG_HAVE_INTRIN_ENDPOINT 1
/* Define this to 1 if you want to compile a version with two endpoints: The
* default control endpoint 0 and an interrupt-in endpoint 1.
*/
#define USB_CFG_HAVE_INTRIN_ENDPOINT3 0
/* Define this to 1 if you want to compile a version with three endpoints: The
* default control endpoint 0, an interrupt-in endpoint 1 and an interrupt-in
* endpoint 3. You must also enable endpoint 1 above.
*/
/* #define USB_INITIAL_DATATOKEN USBPID_DATA0 */
/* The above macro defines the startup condition for data toggling on the
* interrupt/bulk endpoints 1 and 3. Defaults to USBPID_DATA0.
*/
#define USB_CFG_IMPLEMENT_HALT 0
/* Define this to 1 if you also want to implement the ENDPOINT_HALT feature
* for endpoint 1 (interrupt endpoint). Although you may not need this feature,
* it is required by the standard. We have made it a config option because it
* bloats the code considerably.
*/
#define USB_CFG_INTR_POLL_INTERVAL 20
/* If you compile a version with endpoint 1 (interrupt-in), this is the poll
* interval. The value is in milliseconds and must not be less than 10 ms for
* low speed devices.
*/
#define USB_CFG_IS_SELF_POWERED 0
/* Define this to 1 if the device has its own power supply. Set it to 0 if the
* device is powered from the USB bus.
*/
#define USB_CFG_MAX_BUS_POWER 100
/* Set this variable to the maximum USB bus power consumption of your device.
* The value is in milliamperes. [It will be divided by two since USB
* communicates power requirements in units of 2 mA.]
*/
#define USB_CFG_IMPLEMENT_FN_WRITE 0
/* Set this to 1 if you want usbFunctionWrite() to be called for control-out
* transfers. Set it to 0 if you don't need it and want to save a couple of
* bytes.
*/
#define USB_CFG_IMPLEMENT_FN_READ 0
/* Set this to 1 if you need to send control replies which are generated
* "on the fly" when usbFunctionRead() is called. If you only want to send
* data from a static buffer, set it to 0 and return the data from
* usbFunctionSetup(). This saves a couple of bytes.
*/
#define USB_CFG_IMPLEMENT_FN_WRITEOUT 0
/* Define this to 1 if you want to use interrupt-out (or bulk out) endpoint 1.
* You must implement the function usbFunctionWriteOut() which receives all
* interrupt/bulk data sent to endpoint 1.
*/
#define USB_CFG_HAVE_FLOWCONTROL 0
/* Define this to 1 if you want flowcontrol over USB data. See the definition
* of the macros usbDisableAllRequests() and usbEnableAllRequests() in
* usbdrv.h.
*/
/* #define USB_RX_USER_HOOK(data, len) if(usbRxToken == (uchar)USBPID_SETUP) blinkLED(); */
/* This macro is a hook if you want to do unconventional things. If it is
* defined, it's inserted at the beginning of received message processing.
* If you eat the received message and don't want default processing to
* proceed, do a return after doing your things. One possible application
* (besides debugging) is to flash a status LED on each packet.
*/
#define USB_COUNT_SOF 0
/* define this macro to 1 if you need the global variable "usbSofCount" which
* counts SOF packets.
*/
/* -------------------------- Device Description --------------------------- */
#define USB_CFG_VENDOR_ID 0xc0, 0x16
/* USB vendor ID for the device, low byte first. If you have registered your
* own Vendor ID, define it here. Otherwise you use obdev's free shared
* VID/PID pair. Be sure to read USBID-License.txt for rules!
* This template uses obdev's shared VID/PID pair for HIDs: 0x16c0/0x5df.
* Use this VID/PID pair ONLY if you understand the implications!
*/
#define USB_CFG_DEVICE_ID 0xdf, 0x05
/* This is the ID of the product, low byte first. It is interpreted in the
* scope of the vendor ID. If you have registered your own VID with usb.org
* or if you have licensed a PID from somebody else, define it here. Otherwise
* you use obdev's free shared VID/PID pair. Be sure to read the rules in
* USBID-License.txt!
* This template uses obdev's shared VID/PID pair for HIDs: 0x16c0/0x5df.
* Use this VID/PID pair ONLY if you understand the implications!
*/
#define USB_CFG_DEVICE_VERSION 0x00, 0x01
/* Version number of the device: Minor number first, then major number.
*/
#define USB_CFG_VENDOR_NAME 'w', 'w', 'w', '.', 'o', 'b', 'd', 'e', 'v', '.', 'a', 't'
#define USB_CFG_VENDOR_NAME_LEN 12
/* These two values define the vendor name returned by the USB device. The name
* must be given as a list of characters under single quotes. The characters
* are interpreted as Unicode (UTF-16) entities.
* If you don't want a vendor name string, undefine these macros.
* ALWAYS define a vendor name containing your Internet domain name if you use
* obdev's free shared VID/PID pair. See the file USBID-License.txt for
* details.
*/
#define USB_CFG_DEVICE_NAME 'T', 'e', 'm', 'p', 'l', 'a', 't', 'e'
#define USB_CFG_DEVICE_NAME_LEN 8
/* Same as above for the device name. If you don't want a device name, undefine
* the macros. See the file USBID-License.txt before you assign a name if you
* use a shared VID/PID.
*/
/*#define USB_CFG_SERIAL_NUMBER 'N', 'o', 'n', 'e' */
/*#define USB_CFG_SERIAL_NUMBER_LEN 0 */
/* Same as above for the serial number. If you don't want a serial number,
* undefine the macros.
* It may be useful to provide the serial number through other means than at
* compile time. See the section about descriptor properties below for how
* to fine tune control over USB descriptors such as the string descriptor
* for the serial number.
*/
#define USB_CFG_DEVICE_CLASS 0
#define USB_CFG_DEVICE_SUBCLASS 0
/* See USB specification if you want to conform to an existing device class.
*/
#define USB_CFG_INTERFACE_CLASS 3 /* HID */
#define USB_CFG_INTERFACE_SUBCLASS 0
#define USB_CFG_INTERFACE_PROTOCOL 0
/* See USB specification if you want to conform to an existing device class or
* protocol.
* This template defines a HID class device. If you implement a vendor class
* device, set USB_CFG_INTERFACE_CLASS to 0 and USB_CFG_DEVICE_CLASS to 0xff.
*/
#define USB_CFG_HID_REPORT_DESCRIPTOR_LENGTH 42 /* total length of report descriptor */
/* Define this to the length of the HID report descriptor, if you implement
* an HID device. Otherwise don't define it or define it to 0.
* Since this template defines a HID device, it must also specify a HID
* report descriptor length. You must add a PROGMEM character array named
* "usbHidReportDescriptor" to your code which contains the report descriptor.
* Don't forget to keep the array and this define in sync!
*/
/* #define USB_PUBLIC static */
/* Use the define above if you #include usbdrv.c instead of linking against it.
* This technique saves a couple of bytes in flash memory.
*/
/* ------------------- Fine Control over USB Descriptors ------------------- */
/* If you don't want to use the driver's default USB descriptors, you can
* provide our own. These can be provided as (1) fixed length static data in
* flash memory, (2) fixed length static data in RAM or (3) dynamically at
* runtime in the function usbFunctionDescriptor(). See usbdrv.h for more
* information about this function.
* Descriptor handling is configured through the descriptor's properties. If
* no properties are defined or if they are 0, the default descriptor is used.
* Possible properties are:
* + USB_PROP_IS_DYNAMIC: The data for the descriptor should be fetched
* at runtime via usbFunctionDescriptor().
* + USB_PROP_IS_RAM: The data returned by usbFunctionDescriptor() or found
* in static memory is in RAM, not in flash memory.
* + USB_PROP_LENGTH(len): If the data is in static memory (RAM or flash),
* the driver must know the descriptor's length. The descriptor itself is
* found at the address of a well known identifier (see below).
* List of static descriptor names (must be declared PROGMEM if in flash):
* char usbDescriptorDevice[];
* char usbDescriptorConfiguration[];
* char usbDescriptorHidReport[];
* char usbDescriptorString0[];
* int usbDescriptorStringVendor[];
* int usbDescriptorStringDevice[];
* int usbDescriptorStringSerialNumber[];
* Other descriptors can't be provided statically, they must be provided
* dynamically at runtime.
*
* Descriptor properties are or-ed or added together, e.g.:
* #define USB_CFG_DESCR_PROPS_DEVICE (USB_PROP_IS_RAM | USB_PROP_LENGTH(18))
*
* The following descriptors are defined:
* USB_CFG_DESCR_PROPS_DEVICE
* USB_CFG_DESCR_PROPS_CONFIGURATION
* USB_CFG_DESCR_PROPS_STRINGS
* USB_CFG_DESCR_PROPS_STRING_0
* USB_CFG_DESCR_PROPS_STRING_VENDOR
* USB_CFG_DESCR_PROPS_STRING_PRODUCT
* USB_CFG_DESCR_PROPS_STRING_SERIAL_NUMBER
* USB_CFG_DESCR_PROPS_HID
* USB_CFG_DESCR_PROPS_HID_REPORT
* USB_CFG_DESCR_PROPS_UNKNOWN (for all descriptors not handled by the driver)
*
*/
#define USB_CFG_DESCR_PROPS_DEVICE 0
#define USB_CFG_DESCR_PROPS_CONFIGURATION 0
#define USB_CFG_DESCR_PROPS_STRINGS 0
#define USB_CFG_DESCR_PROPS_STRING_0 0
#define USB_CFG_DESCR_PROPS_STRING_VENDOR 0
#define USB_CFG_DESCR_PROPS_STRING_PRODUCT 0
#define USB_CFG_DESCR_PROPS_STRING_SERIAL_NUMBER 0
#define USB_CFG_DESCR_PROPS_HID 0
#define USB_CFG_DESCR_PROPS_HID_REPORT 0
#define USB_CFG_DESCR_PROPS_UNKNOWN 0
/* ----------------------- Optional MCU Description ------------------------ */
/* The following configurations have working defaults in usbdrv.h. You
* usually don't need to set them explicitly. Only if you want to run
* the driver on a device which is not yet supported or with a compiler
* which is not fully supported (such as IAR C) or if you use a differnt
* interrupt than INT0, you may have to define some of these.
*/
/* #define USB_INTR_CFG MCUCR */
/* #define USB_INTR_CFG_SET ((1 << ISC00) | (1 << ISC01)) */
/* #define USB_INTR_CFG_CLR 0 */
/* #define USB_INTR_ENABLE GIMSK */
/* #define USB_INTR_ENABLE_BIT INT0 */
/* #define USB_INTR_PENDING GIFR */
/* #define USB_INTR_PENDING_BIT INTF0 */
/* #define USB_INTR_VECTOR SIG_INTERRUPT0 */
#endif /* __usbconfig_h_included__ */

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/* Name: usbdrvasm12.S
* Project: AVR USB driver
* Author: Christian Starkjohann
* Creation Date: 2004-12-29
* Tabsize: 4
* Copyright: (c) 2007 by OBJECTIVE DEVELOPMENT Software GmbH
* License: GNU GPL v2 (see License.txt) or proprietary (CommercialLicense.txt)
* This Revision: $Id: usbdrvasm12.S,v 1.1 2013-04-25 02:18:15 cvs Exp $
*/
/* Do not link this file! Link usbdrvasm.S instead, which includes the
* appropriate implementation!
*/
/*
General Description:
This file is the 12 MHz version of the asssembler part of the USB driver. It
requires a 12 MHz crystal (not a ceramic resonator and not a calibrated RC
oscillator).
See usbdrv.h for a description of the entire driver.
Since almost all of this code is timing critical, don't change unless you
really know what you are doing! Many parts require not only a maximum number
of CPU cycles, but even an exact number of cycles!
Timing constraints according to spec (in bit times):
timing subject min max CPUcycles
---------------------------------------------------------------------------
EOP of OUT/SETUP to sync pattern of DATA0 (both rx) 2 16 16-128
EOP of IN to sync pattern of DATA0 (rx, then tx) 2 7.5 16-60
DATAx (rx) to ACK/NAK/STALL (tx) 2 7.5 16-60
*/
;Software-receiver engine. Strict timing! Don't change unless you can preserve timing!
;interrupt response time: 4 cycles + insn running = 7 max if interrupts always enabled
;max allowable interrupt latency: 34 cycles -> max 25 cycles interrupt disable
;max stack usage: [ret(2), YL, SREG, YH, shift, x1, x2, x3, cnt, x4] = 11 bytes
;Numbers in brackets are maximum cycles since SOF.
USB_INTR_VECTOR:
;order of registers pushed: YL, SREG [sofError], YH, shift, x1, x2, x3, cnt
push YL ;2 [35] push only what is necessary to sync with edge ASAP
in YL, SREG ;1 [37]
push YL ;2 [39]
;----------------------------------------------------------------------------
; Synchronize with sync pattern:
;----------------------------------------------------------------------------
;sync byte (D-) pattern LSb to MSb: 01010100 [1 = idle = J, 0 = K]
;sync up with J to K edge during sync pattern -- use fastest possible loops
;first part has no timeout because it waits for IDLE or SE1 (== disconnected)
waitForJ:
sbis USBIN, USBMINUS ;1 [40] wait for D- == 1
rjmp waitForJ ;2
waitForK:
;The following code results in a sampling window of 1/4 bit which meets the spec.
sbis USBIN, USBMINUS
rjmp foundK
sbis USBIN, USBMINUS
rjmp foundK
sbis USBIN, USBMINUS
rjmp foundK
sbis USBIN, USBMINUS
rjmp foundK
sbis USBIN, USBMINUS
rjmp foundK
#if USB_COUNT_SOF
lds YL, usbSofCount
inc YL
sts usbSofCount, YL
#endif /* USB_COUNT_SOF */
rjmp sofError
foundK:
;{3, 5} after falling D- edge, average delay: 4 cycles [we want 4 for center sampling]
;we have 1 bit time for setup purposes, then sample again. Numbers in brackets
;are cycles from center of first sync (double K) bit after the instruction
push YH ;2 [2]
lds YL, usbInputBufOffset;2 [4]
clr YH ;1 [5]
subi YL, lo8(-(usbRxBuf));1 [6]
sbci YH, hi8(-(usbRxBuf));1 [7]
sbis USBIN, USBMINUS ;1 [8] we want two bits K [sample 1 cycle too early]
rjmp haveTwoBitsK ;2 [10]
pop YH ;2 [11] undo the push from before
rjmp waitForK ;2 [13] this was not the end of sync, retry
haveTwoBitsK:
;----------------------------------------------------------------------------
; push more registers and initialize values while we sample the first bits:
;----------------------------------------------------------------------------
push shift ;2 [16]
push x1 ;2 [12]
push x2 ;2 [14]
in x1, USBIN ;1 [17] <-- sample bit 0
ldi shift, 0xff ;1 [18]
bst x1, USBMINUS ;1 [19]
bld shift, 0 ;1 [20]
push x3 ;2 [22]
push cnt ;2 [24]
in x2, USBIN ;1 [25] <-- sample bit 1
ser x3 ;1 [26] [inserted init instruction]
eor x1, x2 ;1 [27]
bst x1, USBMINUS ;1 [28]
bld shift, 1 ;1 [29]
ldi cnt, USB_BUFSIZE;1 [30] [inserted init instruction]
rjmp rxbit2 ;2 [32]
;----------------------------------------------------------------------------
; Receiver loop (numbers in brackets are cycles within byte after instr)
;----------------------------------------------------------------------------
unstuff0: ;1 (branch taken)
andi x3, ~0x01 ;1 [15]
mov x1, x2 ;1 [16] x2 contains last sampled (stuffed) bit
in x2, USBIN ;1 [17] <-- sample bit 1 again
ori shift, 0x01 ;1 [18]
rjmp didUnstuff0 ;2 [20]
unstuff1: ;1 (branch taken)
mov x2, x1 ;1 [21] x1 contains last sampled (stuffed) bit
andi x3, ~0x02 ;1 [22]
ori shift, 0x02 ;1 [23]
nop ;1 [24]
in x1, USBIN ;1 [25] <-- sample bit 2 again
rjmp didUnstuff1 ;2 [27]
unstuff2: ;1 (branch taken)
andi x3, ~0x04 ;1 [29]
ori shift, 0x04 ;1 [30]
mov x1, x2 ;1 [31] x2 contains last sampled (stuffed) bit
nop ;1 [32]
in x2, USBIN ;1 [33] <-- sample bit 3
rjmp didUnstuff2 ;2 [35]
unstuff3: ;1 (branch taken)
in x2, USBIN ;1 [34] <-- sample stuffed bit 3 [one cycle too late]
andi x3, ~0x08 ;1 [35]
ori shift, 0x08 ;1 [36]
rjmp didUnstuff3 ;2 [38]
unstuff4: ;1 (branch taken)
andi x3, ~0x10 ;1 [40]
in x1, USBIN ;1 [41] <-- sample stuffed bit 4
ori shift, 0x10 ;1 [42]
rjmp didUnstuff4 ;2 [44]
unstuff5: ;1 (branch taken)
andi x3, ~0x20 ;1 [48]
in x2, USBIN ;1 [49] <-- sample stuffed bit 5
ori shift, 0x20 ;1 [50]
rjmp didUnstuff5 ;2 [52]
unstuff6: ;1 (branch taken)
andi x3, ~0x40 ;1 [56]
in x1, USBIN ;1 [57] <-- sample stuffed bit 6
ori shift, 0x40 ;1 [58]
rjmp didUnstuff6 ;2 [60]
; extra jobs done during bit interval:
; bit 0: store, clear [SE0 is unreliable here due to bit dribbling in hubs]
; bit 1: se0 check
; bit 2: overflow check
; bit 3: recovery from delay [bit 0 tasks took too long]
; bit 4: none
; bit 5: none
; bit 6: none
; bit 7: jump, eor
rxLoop:
eor x3, shift ;1 [0] reconstruct: x3 is 0 at bit locations we changed, 1 at others
in x1, USBIN ;1 [1] <-- sample bit 0
st y+, x3 ;2 [3] store data
ser x3 ;1 [4]
nop ;1 [5]
eor x2, x1 ;1 [6]
bst x2, USBMINUS;1 [7]
bld shift, 0 ;1 [8]
in x2, USBIN ;1 [9] <-- sample bit 1 (or possibly bit 0 stuffed)
andi x2, USBMASK ;1 [10]
breq se0 ;1 [11] SE0 check for bit 1
andi shift, 0xf9 ;1 [12]
didUnstuff0:
breq unstuff0 ;1 [13]
eor x1, x2 ;1 [14]
bst x1, USBMINUS;1 [15]
bld shift, 1 ;1 [16]
rxbit2:
in x1, USBIN ;1 [17] <-- sample bit 2 (or possibly bit 1 stuffed)
andi shift, 0xf3 ;1 [18]
breq unstuff1 ;1 [19] do remaining work for bit 1
didUnstuff1:
subi cnt, 1 ;1 [20]
brcs overflow ;1 [21] loop control
eor x2, x1 ;1 [22]
bst x2, USBMINUS;1 [23]
bld shift, 2 ;1 [24]
in x2, USBIN ;1 [25] <-- sample bit 3 (or possibly bit 2 stuffed)
andi shift, 0xe7 ;1 [26]
breq unstuff2 ;1 [27]
didUnstuff2:
eor x1, x2 ;1 [28]
bst x1, USBMINUS;1 [29]
bld shift, 3 ;1 [30]
didUnstuff3:
andi shift, 0xcf ;1 [31]
breq unstuff3 ;1 [32]
in x1, USBIN ;1 [33] <-- sample bit 4
eor x2, x1 ;1 [34]
bst x2, USBMINUS;1 [35]
bld shift, 4 ;1 [36]
didUnstuff4:
andi shift, 0x9f ;1 [37]
breq unstuff4 ;1 [38]
nop2 ;2 [40]
in x2, USBIN ;1 [41] <-- sample bit 5
eor x1, x2 ;1 [42]
bst x1, USBMINUS;1 [43]
bld shift, 5 ;1 [44]
didUnstuff5:
andi shift, 0x3f ;1 [45]
breq unstuff5 ;1 [46]
nop2 ;2 [48]
in x1, USBIN ;1 [49] <-- sample bit 6
eor x2, x1 ;1 [50]
bst x2, USBMINUS;1 [51]
bld shift, 6 ;1 [52]
didUnstuff6:
cpi shift, 0x02 ;1 [53]
brlo unstuff6 ;1 [54]
nop2 ;2 [56]
in x2, USBIN ;1 [57] <-- sample bit 7
eor x1, x2 ;1 [58]
bst x1, USBMINUS;1 [59]
bld shift, 7 ;1 [60]
didUnstuff7:
cpi shift, 0x04 ;1 [61]
brsh rxLoop ;2 [63] loop control
unstuff7:
andi x3, ~0x80 ;1 [63]
ori shift, 0x80 ;1 [64]
in x2, USBIN ;1 [65] <-- sample stuffed bit 7
nop ;1 [66]
rjmp didUnstuff7 ;2 [68]
;----------------------------------------------------------------------------
; Processing of received packet (numbers in brackets are cycles after end of SE0)
;----------------------------------------------------------------------------
;This is the only non-error exit point for the software receiver loop
;we don't check any CRCs here because there is no time left.
#define token x1
se0: ; [0]
subi cnt, USB_BUFSIZE ;1 [1]
neg cnt ;1 [2]
cpi cnt, 3 ;1 [3]
ldi x2, 1<<USB_INTR_PENDING_BIT ;1 [4]
USB_STORE_PENDING(x2) ;1 [5] clear pending intr and check flag later. SE0 should be over.
brlo doReturn ;1 [6] this is probably an ACK, NAK or similar packet
sub YL, cnt ;1 [7]
sbci YH, 0 ;1 [8]
ld token, y ;2 [10]
cpi token, USBPID_DATA0 ;1 [11]
breq handleData ;1 [12]
cpi token, USBPID_DATA1 ;1 [13]
breq handleData ;1 [14]
ldd x2, y+1 ;2 [16] ADDR and 1 bit endpoint number
mov x3, x2 ;1 [17] store for endpoint number
andi x2, 0x7f ;1 [18] x2 is now ADDR
lds shift, usbDeviceAddr;2 [20]
cp x2, shift ;1 [21]
overflow: ; This is a hack: brcs overflow will never have Z flag set
brne ignorePacket ;1 [22] packet for different address
cpi token, USBPID_IN ;1 [23]
breq handleIn ;1 [24]
cpi token, USBPID_SETUP ;1 [25]
breq handleSetupOrOut ;1 [26]
cpi token, USBPID_OUT ;1 [27]
breq handleSetupOrOut ;1 [28]
; rjmp ignorePacket ;fallthrough, should not happen anyway.
ignorePacket:
clr shift
sts usbCurrentTok, shift
doReturn:
pop cnt
pop x3
pop x2
pop x1
pop shift
pop YH
sofError:
pop YL
out SREG, YL
pop YL
reti
#if USB_CFG_HAVE_INTRIN_ENDPOINT && USB_CFG_HAVE_INTRIN_ENDPOINT3
handleIn3: ;1 [38] (branch taken)
lds cnt, usbTxLen3 ;2 [40]
sbrc cnt, 4 ;2 [42]
rjmp sendCntAndReti ;0 43 + 17 = 60 until SOP
sts usbTxLen3, x1 ;2 [44] x1 == USBPID_NAK from above
ldi YL, lo8(usbTxBuf3) ;1 [45]
ldi YH, hi8(usbTxBuf3) ;1 [46]
rjmp usbSendAndReti ;2 [48] + 13 = 61 until SOP (violates the spec by 1 cycle)
#endif
;Setup and Out are followed by a data packet two bit times (16 cycles) after
;the end of SE0. The sync code allows up to 40 cycles delay from the start of
;the sync pattern until the first bit is sampled. That's a total of 56 cycles.
handleSetupOrOut: ;1 [29] (branch taken)
#if USB_CFG_IMPLEMENT_FN_WRITEOUT /* if we have data for second OUT endpoint, set usbCurrentTok to -1 */
sbrc x3, 7 ;1 [30] skip if endpoint 0
ldi token, -1 ;1 [31] indicate that this is endpoint 1 OUT
#endif
sts usbCurrentTok, token;2 [33]
pop cnt ;2 [35]
pop x3 ;2 [37]
pop x2 ;2 [39]
pop x1 ;2 [41]
pop shift ;2 [43]
pop YH ;2 [45]
USB_LOAD_PENDING(YL) ;1 [46]
sbrc YL, USB_INTR_PENDING_BIT;1 [47] check whether data is already arriving
rjmp waitForJ ;2 [49] save the pops and pushes -- a new interrupt is aready pending
rjmp sofError ;2 not an error, but it does the pops and reti we want
handleData: ;1 [15] (branch taken)
lds token, usbCurrentTok;2 [17]
tst token ;1 [18]
breq doReturn ;1 [19]
lds x2, usbRxLen ;2 [21]
tst x2 ;1 [22]
brne sendNakAndReti ;1 [23]
; 2006-03-11: The following two lines fix a problem where the device was not
; recognized if usbPoll() was called less frequently than once every 4 ms.
cpi cnt, 4 ;1 [24] zero sized data packets are status phase only -- ignore and ack
brmi sendAckAndReti ;1 [25] keep rx buffer clean -- we must not NAK next SETUP
sts usbRxLen, cnt ;2 [27] store received data, swap buffers
sts usbRxToken, token ;2 [29]
lds x2, usbInputBufOffset;2 [31] swap buffers
ldi cnt, USB_BUFSIZE ;1 [32]
sub cnt, x2 ;1 [33]
sts usbInputBufOffset, cnt;2 [35] buffers now swapped
rjmp sendAckAndReti ;2 [37] + 19 = 56 until SOP
handleIn: ;1 [25] (branch taken)
;We don't send any data as long as the C code has not processed the current
;input data and potentially updated the output data. That's more efficient
;in terms of code size than clearing the tx buffers when a packet is received.
lds x1, usbRxLen ;2 [27]
cpi x1, 1 ;1 [28] negative values are flow control, 0 means "buffer free"
brge sendNakAndReti ;1 [29] unprocessed input packet?
ldi x1, USBPID_NAK ;1 [30] prepare value for usbTxLen
#if USB_CFG_HAVE_INTRIN_ENDPOINT
sbrc x3, 7 ;2 [33] x3 contains addr + endpoint
rjmp handleIn1 ;0
#endif
lds cnt, usbTxLen ;2 [34]
sbrc cnt, 4 ;2 [36] all handshake tokens have bit 4 set
rjmp sendCntAndReti ;0 37 + 17 = 54 until SOP
sts usbTxLen, x1 ;2 [38] x1 == USBPID_NAK from above
ldi YL, lo8(usbTxBuf) ;1 [39]
ldi YH, hi8(usbTxBuf) ;1 [40]
rjmp usbSendAndReti ;2 [42] + 14 = 56 until SOP
; Comment about when to set usbTxLen to USBPID_NAK:
; We should set it back when we receive the ACK from the host. This would
; be simple to implement: One static variable which stores whether the last
; tx was for endpoint 0 or 1 and a compare in the receiver to distinguish the
; ACK. However, we set it back immediately when we send the package,
; assuming that no error occurs and the host sends an ACK. We save one byte
; RAM this way and avoid potential problems with endless retries. The rest of
; the driver assumes error-free transfers anyway.
#if USB_CFG_HAVE_INTRIN_ENDPOINT /* placed here due to relative jump range */
handleIn1: ;1 [33] (branch taken)
#if USB_CFG_HAVE_INTRIN_ENDPOINT3
; 2006-06-10 as suggested by O.Tamura: support second INTR IN / BULK IN endpoint
ldd x2, y+2 ;2 [35]
sbrc x2, 0 ;2 [37]
rjmp handleIn3 ;0
#endif
lds cnt, usbTxLen1 ;2 [39]
sbrc cnt, 4 ;2 [41] all handshake tokens have bit 4 set
rjmp sendCntAndReti ;0 42 + 17 = 59 until SOP
sts usbTxLen1, x1 ;2 [43] x1 == USBPID_NAK from above
ldi YL, lo8(usbTxBuf1) ;1 [44]
ldi YH, hi8(usbTxBuf1) ;1 [45]
rjmp usbSendAndReti ;2 [47] + 13 = 60 until SOP
#endif
;----------------------------------------------------------------------------
; Transmitting data
;----------------------------------------------------------------------------
bitstuff0: ;1 (for branch taken)
eor x1, x4 ;1
ldi x2, 0 ;1
out USBOUT, x1 ;1 <-- out
rjmp didStuff0 ;2 branch back 2 cycles earlier
bitstuff1: ;1 (for branch taken)
eor x1, x4 ;1
rjmp didStuff1 ;2 we know that C is clear, jump back to do OUT and ror 0 into x2
bitstuff2: ;1 (for branch taken)
eor x1, x4 ;1
rjmp didStuff2 ;2 jump back 4 cycles earlier and do out and ror 0 into x2
bitstuff3: ;1 (for branch taken)
eor x1, x4 ;1
rjmp didStuff3 ;2 jump back earlier and ror 0 into x2
bitstuff4: ;1 (for branch taken)
eor x1, x4 ;1
ldi x2, 0 ;1
out USBOUT, x1 ;1 <-- out
rjmp didStuff4 ;2 jump back 2 cycles earlier
sendNakAndReti: ;0 [-19] 19 cycles until SOP
ldi x3, USBPID_NAK ;1 [-18]
rjmp usbSendX3 ;2 [-16]
sendAckAndReti: ;0 [-19] 19 cycles until SOP
ldi x3, USBPID_ACK ;1 [-18]
rjmp usbSendX3 ;2 [-16]
sendCntAndReti: ;0 [-17] 17 cycles until SOP
mov x3, cnt ;1 [-16]
usbSendX3: ;0 [-16]
ldi YL, 20 ;1 [-15] 'x3' is R20
ldi YH, 0 ;1 [-14]
ldi cnt, 2 ;1 [-13]
; rjmp usbSendAndReti fallthrough
; USB spec says:
; idle = J
; J = (D+ = 0), (D- = 1) or USBOUT = 0x01
; K = (D+ = 1), (D- = 0) or USBOUT = 0x02
; Spec allows 7.5 bit times from EOP to SOP for replies (= 60 cycles)
;usbSend:
;pointer to data in 'Y'
;number of bytes in 'cnt' -- including sync byte
;uses: x1...x4, shift, cnt, Y
;Numbers in brackets are time since first bit of sync pattern is sent
usbSendAndReti: ;0 [-13] timing: 13 cycles until SOP
in x2, USBDDR ;1 [-12]
ori x2, USBMASK ;1 [-11]
sbi USBOUT, USBMINUS;2 [-9] prepare idle state; D+ and D- must have been 0 (no pullups)
in x1, USBOUT ;1 [-8] port mirror for tx loop
out USBDDR, x2 ;1 [-7] <- acquire bus
; need not init x2 (bitstuff history) because sync starts with 0
push x4 ;2 [-5]
ldi x4, USBMASK ;1 [-4] exor mask
ldi shift, 0x80 ;1 [-3] sync byte is first byte sent
txLoop: ; [62]
sbrs shift, 0 ;1 [-2] [62]
eor x1, x4 ;1 [-1] [63]
out USBOUT, x1 ;1 [0] <-- out bit 0
ror shift ;1 [1]
ror x2 ;1 [2]
didStuff0:
cpi x2, 0xfc ;1 [3]
brsh bitstuff0 ;1 [4]
sbrs shift, 0 ;1 [5]
eor x1, x4 ;1 [6]
ror shift ;1 [7]
didStuff1:
out USBOUT, x1 ;1 [8] <-- out bit 1
ror x2 ;1 [9]
cpi x2, 0xfc ;1 [10]
brsh bitstuff1 ;1 [11]
sbrs shift, 0 ;1 [12]
eor x1, x4 ;1 [13]
ror shift ;1 [14]
didStuff2:
ror x2 ;1 [15]
out USBOUT, x1 ;1 [16] <-- out bit 2
cpi x2, 0xfc ;1 [17]
brsh bitstuff2 ;1 [18]
sbrs shift, 0 ;1 [19]
eor x1, x4 ;1 [20]
ror shift ;1 [21]
didStuff3:
ror x2 ;1 [22]
cpi x2, 0xfc ;1 [23]
out USBOUT, x1 ;1 [24] <-- out bit 3
brsh bitstuff3 ;1 [25]
nop2 ;2 [27]
ld x3, y+ ;2 [29]
sbrs shift, 0 ;1 [30]
eor x1, x4 ;1 [31]
out USBOUT, x1 ;1 [32] <-- out bit 4
ror shift ;1 [33]
ror x2 ;1 [34]
didStuff4:
cpi x2, 0xfc ;1 [35]
brsh bitstuff4 ;1 [36]
sbrs shift, 0 ;1 [37]
eor x1, x4 ;1 [38]
ror shift ;1 [39]
didStuff5:
out USBOUT, x1 ;1 [40] <-- out bit 5
ror x2 ;1 [41]
cpi x2, 0xfc ;1 [42]
brsh bitstuff5 ;1 [43]
sbrs shift, 0 ;1 [44]
eor x1, x4 ;1 [45]
ror shift ;1 [46]
didStuff6:
ror x2 ;1 [47]
out USBOUT, x1 ;1 [48] <-- out bit 6
cpi x2, 0xfc ;1 [49]
brsh bitstuff6 ;1 [50]
sbrs shift, 0 ;1 [51]
eor x1, x4 ;1 [52]
ror shift ;1 [53]
didStuff7:
ror x2 ;1 [54]
cpi x2, 0xfc ;1 [55]
out USBOUT, x1 ;1 [56] <-- out bit 7
brsh bitstuff7 ;1 [57]
mov shift, x3 ;1 [58]
dec cnt ;1 [59]
brne txLoop ;1/2 [60/61]
;make SE0:
cbr x1, USBMASK ;1 [61] prepare SE0 [spec says EOP may be 15 to 18 cycles]
pop x4 ;2 [63]
;brackets are cycles from start of SE0 now
out USBOUT, x1 ;1 [0] <-- out SE0 -- from now 2 bits = 16 cycles until bus idle
nop2 ;2 [2]
;2006-03-06: moved transfer of new address to usbDeviceAddr from C-Code to asm:
;set address only after data packet was sent, not after handshake
lds x2, usbNewDeviceAddr;2 [4]
subi YL, 20 + 2 ;1 [5]
sbci YH, 0 ;1 [6]
breq skipAddrAssign ;2 [8]
sts usbDeviceAddr, x2;0 if not skipped: SE0 is one cycle longer
skipAddrAssign:
;end of usbDeviceAddress transfer
ldi x2, 1<<USB_INTR_PENDING_BIT;1 [9] int0 occurred during TX -- clear pending flag
USB_STORE_PENDING(x2) ;1 [10]
ori x1, USBIDLE ;1 [11]
in x2, USBDDR ;1 [12]
cbr x2, USBMASK ;1 [13] set both pins to input
mov x3, x1 ;1 [14]
cbr x3, USBMASK ;1 [15] configure no pullup on both pins
out USBOUT, x1 ;1 [16] <-- out J (idle) -- end of SE0 (EOP signal)
out USBDDR, x2 ;1 [17] <-- release bus now
out USBOUT, x3 ;1 [18] <-- ensure no pull-up resistors are active
rjmp doReturn
bitstuff5: ;1 (for branch taken)
eor x1, x4 ;1
rjmp didStuff5 ;2 same trick as above...
bitstuff6: ;1 (for branch taken)
eor x1, x4 ;1
rjmp didStuff6 ;2 same trick as above...
bitstuff7: ;1 (for branch taken)
eor x1, x4 ;1
rjmp didStuff7 ;2 same trick as above...

547
usbdrv/usbdrvasm15.S Normal file
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@ -0,0 +1,547 @@
/* Name: usbdrvasm15.S
* Project: AVR USB driver
* Author: contributed by V. Bosch
* Creation Date: 2007-08-06
* Tabsize: 4
* Copyright: (c) 2007 by OBJECTIVE DEVELOPMENT Software GmbH
* License: GNU GPL v2 (see License.txt) or proprietary (CommercialLicense.txt)
* Revision: $Id: usbdrvasm15.S,v 1.1 2013-04-25 02:18:15 cvs Exp $
*/
/* Do not link this file! Link usbdrvasm.S instead, which includes the
* appropriate implementation!
*/
/*
General Description:
This file is the 15 MHz version of the asssembler part of the USB driver. It
requires a 15 MHz crystal (not a ceramic resonator and not a calibrated RC
oscillator).
See usbdrv.h for a description of the entire driver.
Since almost all of this code is timing critical, don't change unless you
really know what you are doing! Many parts require not only a maximum number
of CPU cycles, but even an exact number of cycles!
*/
;max stack usage: [ret(2), YL, SREG, YH, bitcnt, shift, x1, x2, x3, x4, cnt] = 12 bytes
;nominal frequency: 15 MHz -> 10.0 cycles per bit, 80.0 cycles per byte
; Numbers in brackets are clocks counted from center of last sync bit
; when instruction starts
;----------------------------------------------------------------------------
; order of registers pushed:
; YL, SREG [sofError] YH, shift, x1, x2, x3, bitcnt, cnt, x4
;----------------------------------------------------------------------------
USB_INTR_VECTOR:
push YL ;2 push only what is necessary to sync with edge ASAP
in YL, SREG ;1
push YL ;2
;----------------------------------------------------------------------------
; Synchronize with sync pattern:
;
; sync byte (D-) pattern LSb to MSb: 01010100 [1 = idle = J, 0 = K]
; sync up with J to K edge during sync pattern -- use fastest possible loops
; first part has no timeout because it waits for IDLE or SE1 (== disconnected)
;-------------------------------------------------------------------------------
waitForJ: ;-
sbis USBIN, USBMINUS ;1 <-- sample: wait for D- == 1
rjmp waitForJ ;2
;-------------------------------------------------------------------------------
; The following code results in a sampling window of < 1/4 bit
; which meets the spec.
;-------------------------------------------------------------------------------
waitForK: ;-
sbis USBIN, USBMINUS ;1 [00] <-- sample
rjmp foundK ;2 [01]
sbis USBIN, USBMINUS ; <-- sample
rjmp foundK
sbis USBIN, USBMINUS ; <-- sample
rjmp foundK
sbis USBIN, USBMINUS ; <-- sample
rjmp foundK
sbis USBIN, USBMINUS ; <-- sample
rjmp foundK
sbis USBIN, USBMINUS ; <-- sample
rjmp foundK
#if USB_COUNT_SOF
lds YL, usbSofCount
inc YL
sts usbSofCount, YL
#endif /* USB_COUNT_SOF */
rjmp sofError
;------------------------------------------------------------------------------
; {3, 5} after falling D- edge, average delay: 4 cycles [we want 5 for
; center sampling]
; we have 1 bit time for setup purposes, then sample again.
; Numbers in brackets are cycles from center of first sync (double K)
; bit after the instruction
;------------------------------------------------------------------------------
foundK: ;- [02]
lds YL, usbInputBufOffset;2 [03+04] tx loop
push YH ;2 [05+06]
clr YH ;1 [07]
subi YL, lo8(-(usbRxBuf)) ;1 [08] [rx loop init]
sbci YH, hi8(-(usbRxBuf)) ;1 [09] [rx loop init]
push shift ;2 [10+11]
ser shift ;1 [12]
sbis USBIN, USBMINUS ;1 [-1] [13] <--sample:we want two bits K (sample 1 cycle too early)
rjmp haveTwoBitsK ;2 [00] [14]
pop shift ;2 [15+16] undo the push from before
pop YH ;2 [17+18] undo the push from before
rjmp waitForK ;2 [19+20] this was not the end of sync, retry
; The entire loop from waitForK until rjmp waitForK above must not exceed two
; bit times (= 20 cycles).
;----------------------------------------------------------------------------
; push more registers and initialize values while we sample the first bits:
;----------------------------------------------------------------------------
haveTwoBitsK: ;- [01]
push x1 ;2 [02+03]
push x2 ;2 [04+05]
push x3 ;2 [06+07]
push bitcnt ;2 [08+09]
in x1, USBIN ;1 [00] [10] <-- sample bit 0
bst x1, USBMINUS ;1 [01]
bld shift, 0 ;1 [02]
push cnt ;2 [03+04]
ldi cnt, USB_BUFSIZE ;1 [05]
push x4 ;2 [06+07] tx loop
rjmp rxLoop ;2 [08]
;----------------------------------------------------------------------------
; Receiver loop (numbers in brackets are cycles within byte after instr)
;----------------------------------------------------------------------------
unstuff0: ;- [07] (branch taken)
andi x3, ~0x01 ;1 [08]
mov x1, x2 ;1 [09] x2 contains last sampled (stuffed) bit
in x2, USBIN ;1 [00] [10] <-- sample bit 1 again
andi x2, USBMASK ;1 [01]
breq se0Hop ;1 [02] SE0 check for bit 1
ori shift, 0x01 ;1 [03] 0b00000001
nop ;1 [04]
rjmp didUnstuff0 ;2 [05]
;-----------------------------------------------------
unstuff1: ;- [05] (branch taken)
mov x2, x1 ;1 [06] x1 contains last sampled (stuffed) bit
andi x3, ~0x02 ;1 [07]
ori shift, 0x02 ;1 [08] 0b00000010
nop ;1 [09]
in x1, USBIN ;1 [00] [10] <-- sample bit 2 again
andi x1, USBMASK ;1 [01]
breq se0Hop ;1 [02] SE0 check for bit 2
rjmp didUnstuff1 ;2 [03]
;-----------------------------------------------------
unstuff2: ;- [05] (branch taken)
andi x3, ~0x04 ;1 [06]
ori shift, 0x04 ;1 [07] 0b00000100
mov x1, x2 ;1 [08] x2 contains last sampled (stuffed) bit
nop ;1 [09]
in x2, USBIN ;1 [00] [10] <-- sample bit 3
andi x2, USBMASK ;1 [01]
breq se0Hop ;1 [02] SE0 check for bit 3
rjmp didUnstuff2 ;2 [03]
;-----------------------------------------------------
unstuff3: ;- [00] [10] (branch taken)
in x2, USBIN ;1 [01] [11] <-- sample stuffed bit 3 one cycle too late
andi x2, USBMASK ;1 [02]
breq se0Hop ;1 [03] SE0 check for stuffed bit 3
andi x3, ~0x08 ;1 [04]
ori shift, 0x08 ;1 [05] 0b00001000
rjmp didUnstuff3 ;2 [06]
;----------------------------------------------------------------------------
; extra jobs done during bit interval:
;
; bit 0: store, clear [SE0 is unreliable here due to bit dribbling in hubs],
; overflow check, jump to the head of rxLoop
; bit 1: SE0 check
; bit 2: SE0 check, recovery from delay [bit 0 tasks took too long]
; bit 3: SE0 check, recovery from delay [bit 0 tasks took too long]
; bit 4: SE0 check, none
; bit 5: SE0 check, none
; bit 6: SE0 check, none
; bit 7: SE0 check, reconstruct: x3 is 0 at bit locations we changed, 1 at others
;----------------------------------------------------------------------------
rxLoop: ;- [09]
in x2, USBIN ;1 [00] [10] <-- sample bit 1 (or possibly bit 0 stuffed)
andi x2, USBMASK ;1 [01]
brne SkipSe0Hop ;1 [02]
se0Hop: ;- [02]
rjmp se0 ;2 [03] SE0 check for bit 1
SkipSe0Hop: ;- [03]
ser x3 ;1 [04]
andi shift, 0xf9 ;1 [05] 0b11111001
breq unstuff0 ;1 [06]
didUnstuff0: ;- [06]
eor x1, x2 ;1 [07]
bst x1, USBMINUS ;1 [08]
bld shift, 1 ;1 [09]
in x1, USBIN ;1 [00] [10] <-- sample bit 2 (or possibly bit 1 stuffed)
andi x1, USBMASK ;1 [01]
breq se0Hop ;1 [02] SE0 check for bit 2
andi shift, 0xf3 ;1 [03] 0b11110011
breq unstuff1 ;1 [04] do remaining work for bit 1
didUnstuff1: ;- [04]
eor x2, x1 ;1 [05]
bst x2, USBMINUS ;1 [06]
bld shift, 2 ;1 [07]
nop2 ;2 [08+09]
in x2, USBIN ;1 [00] [10] <-- sample bit 3 (or possibly bit 2 stuffed)
andi x2, USBMASK ;1 [01]
breq se0Hop ;1 [02] SE0 check for bit 3
andi shift, 0xe7 ;1 [03] 0b11100111
breq unstuff2 ;1 [04]
didUnstuff2: ;- [04]
eor x1, x2 ;1 [05]
bst x1, USBMINUS ;1 [06]
bld shift, 3 ;1 [07]
didUnstuff3: ;- [07]
andi shift, 0xcf ;1 [08] 0b11001111
breq unstuff3 ;1 [09]
in x1, USBIN ;1 [00] [10] <-- sample bit 4
andi x1, USBMASK ;1 [01]
breq se0Hop ;1 [02] SE0 check for bit 4
eor x2, x1 ;1 [03]
bst x2, USBMINUS ;1 [04]
bld shift, 4 ;1 [05]
didUnstuff4: ;- [05]
andi shift, 0x9f ;1 [06] 0b10011111
breq unstuff4 ;1 [07]
nop2 ;2 [08+09]
in x2, USBIN ;1 [00] [10] <-- sample bit 5
andi x2, USBMASK ;1 [01]
breq se0 ;1 [02] SE0 check for bit 5
eor x1, x2 ;1 [03]
bst x1, USBMINUS ;1 [04]
bld shift, 5 ;1 [05]
didUnstuff5: ;- [05]
andi shift, 0x3f ;1 [06] 0b00111111
breq unstuff5 ;1 [07]
nop2 ;2 [08+09]
in x1, USBIN ;1 [00] [10] <-- sample bit 6
andi x1, USBMASK ;1 [01]
breq se0 ;1 [02] SE0 check for bit 6
eor x2, x1 ;1 [03]
bst x2, USBMINUS ;1 [04]
bld shift, 6 ;1 [05]
didUnstuff6: ;- [05]
cpi shift, 0x02 ;1 [06] 0b00000010
brlo unstuff6 ;1 [07]
nop2 ;2 [08+09]
in x2, USBIN ;1 [00] [10] <-- sample bit 7
andi x2, USBMASK ;1 [01]
breq se0 ;1 [02] SE0 check for bit 7
eor x1, x2 ;1 [03]
bst x1, USBMINUS ;1 [04]
bld shift, 7 ;1 [05]
didUnstuff7: ;- [05]
cpi shift, 0x04 ;1 [06] 0b00000100
brlo unstuff7 ;1 [07]
eor x3, shift ;1 [08] reconstruct: x3 is 0 at bit locations we changed, 1 at others
nop ;1 [09]
in x1, USBIN ;1 [00] [10] <-- sample bit 0
st y+, x3 ;2 [01+02] store data
eor x2, x1 ;1 [03]
bst x2, USBMINUS ;1 [04]
bld shift, 0 ;1 [05]
subi cnt, 1 ;1 [06]
brcs ignorePacket ;1 [07]
rjmp rxLoop ;2 [08]
;-----------------------------------------------------
unstuff4: ;- [08]
andi x3, ~0x10 ;1 [09]
in x1, USBIN ;1 [00] [10] <-- sample stuffed bit 4
andi x1, USBMASK ;1 [01]
breq se0 ;1 [02] SE0 check for stuffed bit 4
ori shift, 0x10 ;1 [03]
rjmp didUnstuff4 ;2 [04]
;-----------------------------------------------------
unstuff5: ;- [08]
ori shift, 0x20 ;1 [09]
in x2, USBIN ;1 [00] [10] <-- sample stuffed bit 5
andi x2, USBMASK ;1 [01]
breq se0 ;1 [02] SE0 check for stuffed bit 5
andi x3, ~0x20 ;1 [03]
rjmp didUnstuff5 ;2 [04]
;-----------------------------------------------------
unstuff6: ;- [08]
andi x3, ~0x40 ;1 [09]
in x1, USBIN ;1 [00] [10] <-- sample stuffed bit 6
andi x1, USBMASK ;1 [01]
breq se0 ;1 [02] SE0 check for stuffed bit 6
ori shift, 0x40 ;1 [03]
rjmp didUnstuff6 ;2 [04]
;-----------------------------------------------------
unstuff7: ;- [08]
andi x3, ~0x80 ;1 [09]
in x2, USBIN ;1 [00] [10] <-- sample stuffed bit 7
andi x2, USBMASK ;1 [01]
breq se0 ;1 [02] SE0 check for stuffed bit 7
ori shift, 0x80 ;1 [03]
rjmp didUnstuff7 ;2 [04]
;----------------------------------------------------------------------------
; Processing of received packet (numbers in brackets are cycles after center of SE0)
;----------------------------------------------------------------------------
;This is the only non-error exit point for the software receiver loop
;we don't check any CRCs here because there is no time left.
#define token x1
se0: ;- [04]
subi cnt, USB_BUFSIZE ;1 [05]
neg cnt ;1 [06]
cpi cnt, 3 ;1 [07]
ldi x2, 1<<USB_INTR_PENDING_BIT ;1 [08]
USB_STORE_PENDING(x2) ;1 [09] clear pending intr and check flag later. SE0 should be over.
brlo doReturn ;1 [10] this is probably an ACK, NAK or similar packet
sub YL, cnt ;1 [11]
sbci YH, 0 ;1 [12]
ld token, y ;2 [13+14]
cpi token, USBPID_DATA0 ;1 [15]
breq handleData ;1 [16]
cpi token, USBPID_DATA1 ;1 [17]
breq handleData ;1 [18]
ldd x2, y+1 ;2 [19+20] ADDR and 1 bit endpoint number
mov x3, x2 ;1 [21] store for endpoint number
andi x2, 0x7f ;1 [22] x2 is now ADDR
lds shift, usbDeviceAddr ;2 [23+24]
cp x2, shift ;1 [25]
brne ignorePacket ;1 [26] packet for different address
cpi token, USBPID_IN ;1 [27]
breq handleIn ;1 [28]
cpi token, USBPID_SETUP ;1 [29]
breq handleSetupOrOut ;1 [30]
cpi token, USBPID_OUT ;1 [31]
breq handleSetupOrOut ;1 [32]
; rjmp ignorePacket ; fallthrough, should not happen anyway.
ignorePacket: ;- [32]
clr shift ;1 [33]
sts usbCurrentTok, shift ;2 [34+35]
doReturn:
pop x4
pop cnt
pop bitcnt
pop x3
pop x2
pop x1
pop shift
pop YH
sofError:
pop YL
out SREG, YL
pop YL
reti
;-------------------------------------------------------------------------
#if USB_CFG_HAVE_INTRIN_ENDPOINT && USB_CFG_HAVE_INTRIN_ENDPOINT3
handleIn3: ;- [42]
lds cnt, usbTxLen3 ;2 [43+44]
sbrc cnt, 4 ;1 [45]
rjmp sendCntAndReti ;1 [46] 46 + 16 = 62 until SOP
sts usbTxLen3, x1 ;2 [47+48] x1 == USBPID_NAK from above
ldi YL, lo8(usbTxBuf3) ;1 [49]
ldi YH, hi8(usbTxBuf3) ;1 [50]
rjmp usbSendAndReti ;1 [51] 51 + 13 = 64 until SOP
#endif
;Setup and Out are followed by a data packet two bit times (20 cycles) after
;the end of SE0. The sync code allows up to 50 cycles delay from the start of
;the sync pattern until the first bit is sampled. That's a total of 70 cycles.
handleSetupOrOut: ;[31/33]
#if USB_CFG_IMPLEMENT_FN_WRITEOUT /* if we have data for second OUT endpoint, set usbCurrentTok to -1 */
sbrc x3, 7 ;[32] skip if endpoint 0
ldi token, -1 ;[33] indicate that this is endpoint 1 OUT
#endif
sts usbCurrentTok, token ;[34+35]
pop x4 ;[36+37]
pop cnt ;[38+39]
pop bitcnt ;[40+41]
pop x3 ;[42+43]
pop x2 ;[44+45]
pop x1 ;[46+47]
pop shift ;[48+49]
pop YH ;[50+51]
USB_LOAD_PENDING(YL) ;[52]
sbrc YL, USB_INTR_PENDING_BIT ;[53] check whether data is already arriving
rjmp waitForJ ;[54] save the pops and pushes -- a new interrupt is aready pending
rjmp sofError ;[55] not an error, but it does the pops and reti we want
;--------------------------------------------------------------------
handleData: ;- [16/18]
lds token, usbCurrentTok ;2 [19+20]
tst token ;1 [21]
breq doReturn ;1 [22]
lds x2, usbRxLen ;2 [23+24]
tst x2 ;1 [25]
brne sendNakAndReti ;1 [26]
; 2006-03-11: The following two lines fix a problem where the device was not
; recognized if usbPoll() was called less frequently than once every 4 ms.
cpi cnt, 4 ;1 [27] 0 sized data packets are status phase only -- ignore and ack
brmi sendAckAndReti ;1 [28] keep rx buffer clean -- we must not NAK next SETUP
sts usbRxLen, cnt ;2 [29+30] store received data, swap buffers
sts usbRxToken, token ;2 [31+23]
lds x2, usbInputBufOffset ;2 [33+34] swap buffers
ldi cnt, USB_BUFSIZE ;1 [35]
sub cnt, x2 ;1 [36]
sts usbInputBufOffset, cnt ;2 [37+38] buffers now swapped
rjmp sendAckAndReti ;1 [39] 39 + 17 = 56 until SOP
;--------------------------------------------------------------------
;We don't send any data as long as the C code has not processed the current
;input data and potentially updated the output data. That's more efficient
;in terms of code size than clearing the tx buffers when a packet is received.
handleIn: ;- [29]
lds x1, usbRxLen ;2 [30+31]
cpi x1, 1 ;1 [32] negative values are flow control, 0 means "buffer free"
brge sendNakAndReti ;1 [33] unprocessed input packet?
ldi x1, USBPID_NAK ;1 [34] prepare value for usbTxLen
#if USB_CFG_HAVE_INTRIN_ENDPOINT
sbrc x3, 7 ;1 [35] x3 contains addr + endpoint
rjmp handleIn1 ;1 [36]
#endif
lds cnt, usbTxLen ;2 [37+38]
sbrc cnt, 4 ;2 [39] all handshake tokens have bit 4 set
rjmp sendCntAndReti ;1 [40] 42 + 16 = 58 until SOP
sts usbTxLen, x1 ;2 [41+42] x1 == USBPID_NAK from above
ldi YL, lo8(usbTxBuf) ;1 [43]
ldi YH, hi8(usbTxBuf) ;1 [44]
rjmp usbSendAndReti ;1 [45] 45 + 13 = 58 until SOP
;---------------------------------------------------------------------------------------
; Comment about when to set usbTxLen to USBPID_NAK:
; We should set it back when we receive the ACK from the host. This would
; be simple to implement: One static variable which stores whether the last
; tx was for endpoint 0 or 1 and a compare in the receiver to distinguish the
; ACK. However, we set it back immediately when we send the package,
; assuming that no error occurs and the host sends an ACK. We save one byte
; RAM this way and avoid potential problems with endless retries. The rest of
; the driver assumes error-free transfers anyway.
#if USB_CFG_HAVE_INTRIN_ENDPOINT /* placed here due to relative jump range */
handleIn1: ;- [37]
#if USB_CFG_HAVE_INTRIN_ENDPOINT3
; 2006-06-10 as suggested by O.Tamura: support second INTR IN / BULK IN endpoint
ldd x2, y+2 ;2 [38+39]
sbrc x2, 0 ;2 [40]
rjmp handleIn3 ;1 [41]
#endif
lds cnt, usbTxLen1 ;2 [42+43]
sbrc cnt, 4 ;2 [44] all handshake tokens have bit 4 set
rjmp sendCntAndReti ;1 [45] 45 + 16 = 61 until SOP
sts usbTxLen1, x1 ;2 [46+47] x1 == USBPID_NAK from above
ldi YL, lo8(usbTxBuf1) ;1 [48]
ldi YH, hi8(usbTxBuf1) ;1 [49]
rjmp usbSendAndReti ;1 [50] 50 + 13 + 63 until SOP
#endif
;---------------------------------------------------------------------------
; USB spec says:
; idle = J
; J = (D+ = 0), (D- = 1)
; K = (D+ = 1), (D- = 0)
; Spec allows 7.5 bit times from EOP to SOP for replies
;---------------------------------------------------------------------------
bitstuffN: ;- [04]
eor x1, x4 ;1 [05]
clr x2 ;1 [06]
nop ;1 [07]
rjmp didStuffN ;1 [08]
;---------------------------------------------------------------------------
bitstuff6: ;- [04]
eor x1, x4 ;1 [05]
clr x2 ;1 [06]
rjmp didStuff6 ;1 [07]
;---------------------------------------------------------------------------
bitstuff7: ;- [02]
eor x1, x4 ;1 [03]
clr x2 ;1 [06]
nop ;1 [05]
rjmp didStuff7 ;1 [06]
;---------------------------------------------------------------------------
sendNakAndReti: ;- [-19]
ldi x3, USBPID_NAK ;1 [-18]
rjmp sendX3AndReti ;1 [-17]
;---------------------------------------------------------------------------
sendAckAndReti: ;- [-17]
ldi cnt, USBPID_ACK ;1 [-16]
sendCntAndReti: ;- [-16]
mov x3, cnt ;1 [-15]
sendX3AndReti: ;- [-15]
ldi YL, 20 ;1 [-14] x3==r20 address is 20
ldi YH, 0 ;1 [-13]
ldi cnt, 2 ;1 [-12]
; rjmp usbSendAndReti fallthrough
;---------------------------------------------------------------------------
;usbSend:
;pointer to data in 'Y'
;number of bytes in 'cnt' -- including sync byte [range 2 ... 12]
;uses: x1...x4, btcnt, shift, cnt, Y
;Numbers in brackets are time since first bit of sync pattern is sent
;We need not to match the transfer rate exactly because the spec demands
;only 1.5% precision anyway.
usbSendAndReti: ;- [-13] 13 cycles until SOP
in x2, USBDDR ;1 [-12]
ori x2, USBMASK ;1 [-11]
sbi USBOUT, USBMINUS ;2 [-09-10] prepare idle state; D+ and D- must have been 0 (no pullups)
in x1, USBOUT ;1 [-08] port mirror for tx loop
out USBDDR, x2 ;1 [-07] <- acquire bus
; need not init x2 (bitstuff history) because sync starts with 0
ldi x4, USBMASK ;1 [-06] exor mask
ldi shift, 0x80 ;1 [-05] sync byte is first byte sent
ldi bitcnt, 6 ;1 [-04]
txBitLoop: ;- [-04] [06]
sbrs shift, 0 ;1 [-03] [07]
eor x1, x4 ;1 [-02] [08]
ror shift ;1 [-01] [09]
didStuffN: ;- [09]
out USBOUT, x1 ;1 [00] [10] <-- out N
ror x2 ;1 [01]
cpi x2, 0xfc ;1 [02]
brcc bitstuffN ;1 [03]
dec bitcnt ;1 [04]
brne txBitLoop ;1 [05]
sbrs shift, 0 ;1 [06]
eor x1, x4 ;1 [07]
ror shift ;1 [08]
didStuff6: ;- [08]
nop ;1 [09]
out USBOUT, x1 ;1 [00] [10] <-- out 6
ror x2 ;1 [01]
cpi x2, 0xfc ;1 [02]
brcc bitstuff6 ;1 [03]
sbrs shift, 0 ;1 [04]
eor x1, x4 ;1 [05]
ror shift ;1 [06]
ror x2 ;1 [07]
didStuff7: ;- [07]
ldi bitcnt, 6 ;1 [08]
cpi x2, 0xfc ;1 [09]
out USBOUT, x1 ;1 [00] [10] <-- out 7
brcc bitstuff7 ;1 [01]
ld shift, y+ ;2 [02+03]
dec cnt ;1 [04]
brne txBitLoop ;1 [05]
makeSE0:
cbr x1, USBMASK ;1 [06] prepare SE0 [spec says EOP may be 19 to 23 cycles]
lds x2, usbNewDeviceAddr;2 [07+08]
;2006-03-06: moved transfer of new address to usbDeviceAddr from C-Code to asm:
;set address only after data packet was sent, not after handshake
subi YL, 2 ;1 [09]
out USBOUT, x1 ;1 [00] [10] <-- out SE0-- from now 2 bits==20 cycl. until bus idle
sbci YH, 0 ;1 [01]
breq skipAddrAssign ;1 [02]
sts usbDeviceAddr, x2 ;2 [03+04] if not skipped: SE0 is one cycle longer
;----------------------------------------------------------------------------
;end of usbDeviceAddress transfer
skipAddrAssign: ;- [03/04]
ldi x2, 1<<USB_INTR_PENDING_BIT ;1 [04] int0 occurred during TX -- clear pending flag
USB_STORE_PENDING(x2) ;1 [05]
ori x1, USBIDLE ;1 [06]
in x2, USBDDR ;1 [07]
cbr x2, USBMASK ;1 [08] set both pins to input
mov x3, x1 ;1 [09]
cbr x3, USBMASK ;1 [10] configure no pullup on both pins
ldi x4, 3 ;1 [11]
se0Delay: ;- [11] [14]
dec x4 ;1 [12] [15]
brne se0Delay ;1 [13] [16]
nop2 ;2 [17+18]
out USBOUT, x1 ;1 [19] <--out J (idle) -- end of SE0 (EOP sig.)
out USBDDR, x2 ;1 [20] <--release bus now
out USBOUT, x3 ;1 [21] <--ensure no pull-up resistors are active
rjmp doReturn ;1 [22]
;---------------------------------------------------------------------------

472
usbdrv/usbdrvasm16.S Normal file
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@ -0,0 +1,472 @@
/* Name: usbdrvasm16.S
* Project: AVR USB driver
* Author: Christian Starkjohann
* Creation Date: 2007-06-15
* Tabsize: 4
* Copyright: (c) 2007 by OBJECTIVE DEVELOPMENT Software GmbH
* License: GNU GPL v2 (see License.txt) or proprietary (CommercialLicense.txt)
* Revision: $Id: usbdrvasm16.S,v 1.1 2013-04-25 02:18:15 cvs Exp $
*/
/* Do not link this file! Link usbdrvasm.S instead, which includes the
* appropriate implementation!
*/
/*
General Description:
This file is the 16 MHz version of the asssembler part of the USB driver. It
requires a 16 MHz crystal (not a ceramic resonator and not a calibrated RC
oscillator).
See usbdrv.h for a description of the entire driver.
Since almost all of this code is timing critical, don't change unless you
really know what you are doing! Many parts require not only a maximum number
of CPU cycles, but even an exact number of cycles!
*/
;max stack usage: [ret(2), YL, SREG, YH, bitcnt, shift, x1, x2, x3, x4, cnt] = 12 bytes
;nominal frequency: 16 MHz -> 10.6666666 cycles per bit, 85.333333333 cycles per byte
; Numbers in brackets are clocks counted from center of last sync bit
; when instruction starts
USB_INTR_VECTOR:
;order of registers pushed: YL, SREG YH, [sofError], bitcnt, shift, x1, x2, x3, x4, cnt
push YL ;[-25] push only what is necessary to sync with edge ASAP
in YL, SREG ;[-23]
push YL ;[-22]
push YH ;[-20]
;----------------------------------------------------------------------------
; Synchronize with sync pattern:
;----------------------------------------------------------------------------
;sync byte (D-) pattern LSb to MSb: 01010100 [1 = idle = J, 0 = K]
;sync up with J to K edge during sync pattern -- use fastest possible loops
;first part has no timeout because it waits for IDLE or SE1 (== disconnected)
waitForJ:
sbis USBIN, USBMINUS ;[-18] wait for D- == 1
rjmp waitForJ
waitForK:
;The following code results in a sampling window of < 1/4 bit which meets the spec.
sbis USBIN, USBMINUS ;[-15]
rjmp foundK ;[-14]
sbis USBIN, USBMINUS
rjmp foundK
sbis USBIN, USBMINUS
rjmp foundK
sbis USBIN, USBMINUS
rjmp foundK
sbis USBIN, USBMINUS
rjmp foundK
sbis USBIN, USBMINUS
rjmp foundK
#if USB_COUNT_SOF
lds YL, usbSofCount
inc YL
sts usbSofCount, YL
#endif /* USB_COUNT_SOF */
rjmp sofError
foundK: ;[-12]
;{3, 5} after falling D- edge, average delay: 4 cycles [we want 5 for center sampling]
;we have 1 bit time for setup purposes, then sample again. Numbers in brackets
;are cycles from center of first sync (double K) bit after the instruction
push bitcnt ;[-12]
; [---] ;[-11]
lds YL, usbInputBufOffset;[-10]
; [---] ;[-9]
clr YH ;[-8]
subi YL, lo8(-(usbRxBuf));[-7] [rx loop init]
sbci YH, hi8(-(usbRxBuf));[-6] [rx loop init]
push shift ;[-5]
; [---] ;[-4]
ldi bitcnt, 0x55 ;[-3] [rx loop init]
sbis USBIN, USBMINUS ;[-2] we want two bits K (sample 2 cycles too early)
rjmp haveTwoBitsK ;[-1]
pop shift ;[0] undo the push from before
pop bitcnt ;[2] undo the push from before
rjmp waitForK ;[4] this was not the end of sync, retry
; The entire loop from waitForK until rjmp waitForK above must not exceed two
; bit times (= 21 cycles).
;----------------------------------------------------------------------------
; push more registers and initialize values while we sample the first bits:
;----------------------------------------------------------------------------
haveTwoBitsK:
push x1 ;[1]
push x2 ;[3]
push x3 ;[5]
ldi shift, 0 ;[7]
ldi x3, 1<<4 ;[8] [rx loop init] first sample is inverse bit, compensate that
push x4 ;[9] == leap
in x1, USBIN ;[11] <-- sample bit 0
andi x1, USBMASK ;[12]
bst x1, USBMINUS ;[13]
bld shift, 7 ;[14]
push cnt ;[15]
ldi leap, 0 ;[17] [rx loop init]
ldi cnt, USB_BUFSIZE;[18] [rx loop init]
rjmp rxbit1 ;[19] arrives at [21]
;----------------------------------------------------------------------------
; Receiver loop (numbers in brackets are cycles within byte after instr)
;----------------------------------------------------------------------------
unstuff6:
andi x2, USBMASK ;[03]
ori x3, 1<<6 ;[04] will not be shifted any more
andi shift, ~0x80;[05]
mov x1, x2 ;[06] sampled bit 7 is actually re-sampled bit 6
subi leap, 3 ;[07] since this is a short (10 cycle) bit, enforce leap bit
rjmp didUnstuff6 ;[08]
unstuff7:
ori x3, 1<<7 ;[09] will not be shifted any more
in x2, USBIN ;[00] [10] re-sample bit 7
andi x2, USBMASK ;[01]
andi shift, ~0x80;[02]
subi leap, 3 ;[03] since this is a short (10 cycle) bit, enforce leap bit
rjmp didUnstuff7 ;[04]
unstuffEven:
ori x3, 1<<6 ;[09] will be shifted right 6 times for bit 0
in x1, USBIN ;[00] [10]
andi shift, ~0x80;[01]
andi x1, USBMASK ;[02]
breq se0 ;[03]
subi leap, 3 ;[04] since this is a short (10 cycle) bit, enforce leap bit
nop ;[05]
rjmp didUnstuffE ;[06]
unstuffOdd:
ori x3, 1<<5 ;[09] will be shifted right 4 times for bit 1
in x2, USBIN ;[00] [10]
andi shift, ~0x80;[01]
andi x2, USBMASK ;[02]
breq se0 ;[03]
subi leap, 3 ;[04] since this is a short (10 cycle) bit, enforce leap bit
nop ;[05]
rjmp didUnstuffO ;[06]
rxByteLoop:
andi x1, USBMASK ;[03]
eor x2, x1 ;[04]
subi leap, 1 ;[05]
brpl skipLeap ;[06]
subi leap, -3 ;1 one leap cycle every 3rd byte -> 85 + 1/3 cycles per byte
nop ;1
skipLeap:
subi x2, 1 ;[08]
ror shift ;[09]
didUnstuff6:
cpi shift, 0xfc ;[10]
in x2, USBIN ;[00] [11] <-- sample bit 7
brcc unstuff6 ;[01]
andi x2, USBMASK ;[02]
eor x1, x2 ;[03]
subi x1, 1 ;[04]
ror shift ;[05]
didUnstuff7:
cpi shift, 0xfc ;[06]
brcc unstuff7 ;[07]
eor x3, shift ;[08] reconstruct: x3 is 1 at bit locations we changed, 0 at others
st y+, x3 ;[09] store data
rxBitLoop:
in x1, USBIN ;[00] [11] <-- sample bit 0/2/4
andi x1, USBMASK ;[01]
eor x2, x1 ;[02]
andi x3, 0x3f ;[03] topmost two bits reserved for 6 and 7
subi x2, 1 ;[04]
ror shift ;[05]
cpi shift, 0xfc ;[06]
brcc unstuffEven ;[07]
didUnstuffE:
lsr x3 ;[08]
lsr x3 ;[09]
rxbit1:
in x2, USBIN ;[00] [10] <-- sample bit 1/3/5
andi x2, USBMASK ;[01]
breq se0 ;[02]
eor x1, x2 ;[03]
subi x1, 1 ;[04]
ror shift ;[05]
cpi shift, 0xfc ;[06]
brcc unstuffOdd ;[07]
didUnstuffO:
subi bitcnt, 0xab;[08] == addi 0x55, 0x55 = 0x100/3
brcs rxBitLoop ;[09]
subi cnt, 1 ;[10]
in x1, USBIN ;[00] [11] <-- sample bit 6
brcc rxByteLoop ;[01]
rjmp ignorePacket; overflow
;----------------------------------------------------------------------------
; Processing of received packet (numbers in brackets are cycles after center of SE0)
;----------------------------------------------------------------------------
;This is the only non-error exit point for the software receiver loop
;we don't check any CRCs here because there is no time left.
#define token x1
se0:
subi cnt, USB_BUFSIZE ;[5]
neg cnt ;[6]
cpi cnt, 3 ;[7]
ldi x2, 1<<USB_INTR_PENDING_BIT ;[8]
USB_STORE_PENDING(x2) ;[9] clear pending intr and check flag later. SE0 should be over.
brlo doReturn ;[10] this is probably an ACK, NAK or similar packet
sub YL, cnt ;[11]
sbci YH, 0 ;[12]
ld token, y ;[13]
cpi token, USBPID_DATA0 ;[15]
breq handleData ;[16]
cpi token, USBPID_DATA1 ;[17]
breq handleData ;[18]
ldd x2, y+1 ;[19] ADDR and 1 bit endpoint number
mov x3, x2 ;[21] store for endpoint number
andi x2, 0x7f ;[22] x2 is now ADDR
lds shift, usbDeviceAddr;[23]
cp x2, shift ;[25]
overflow: ; This is a hack: brcs overflow will never have Z flag set
brne ignorePacket ;[26] packet for different address
cpi token, USBPID_IN ;[27]
breq handleIn ;[28]
cpi token, USBPID_SETUP ;[29]
breq handleSetupOrOut ;[30]
cpi token, USBPID_OUT ;[31]
breq handleSetupOrOut ;[32]
; rjmp ignorePacket ;fallthrough, should not happen anyway.
ignorePacket:
clr shift
sts usbCurrentTok, shift
doReturn:
pop cnt
pop x4
pop x3
pop x2
pop x1
pop shift
pop bitcnt
sofError:
pop YH
pop YL
out SREG, YL
pop YL
reti
;Setup and Out are followed by a data packet two bit times (16 cycles) after
;the end of SE0. The sync code allows up to 40 cycles delay from the start of
;the sync pattern until the first bit is sampled. That's a total of 56 cycles.
handleSetupOrOut: ;[34]
#if USB_CFG_IMPLEMENT_FN_WRITEOUT /* if we have data for second OUT endpoint, set usbCurrentTok to -1 */
sbrc x3, 7 ;[34] skip if endpoint 0
ldi token, -1 ;[35] indicate that this is endpoint 1 OUT
#endif
sts usbCurrentTok, token;[36]
pop cnt ;[38]
pop x4 ;[40]
pop x3 ;[42]
pop x2 ;[44]
pop x1 ;[46]
pop shift ;[48]
pop bitcnt ;[50]
USB_LOAD_PENDING(YL) ;[52]
sbrc YL, USB_INTR_PENDING_BIT;[53] check whether data is already arriving
rjmp waitForJ ;[54] save the pops and pushes -- a new interrupt is aready pending
rjmp sofError ;[55] not an error, but it does the pops and reti we want
handleData:
lds token, usbCurrentTok;[20]
tst token ;[22]
breq doReturn ;[23]
lds x2, usbRxLen ;[24]
tst x2 ;[26]
brne sendNakAndReti ;[27]
; 2006-03-11: The following two lines fix a problem where the device was not
; recognized if usbPoll() was called less frequently than once every 4 ms.
cpi cnt, 4 ;[28] zero sized data packets are status phase only -- ignore and ack
brmi sendAckAndReti ;[29] keep rx buffer clean -- we must not NAK next SETUP
sts usbRxLen, cnt ;[30] store received data, swap buffers
sts usbRxToken, token ;[32]
lds x2, usbInputBufOffset;[34] swap buffers
ldi cnt, USB_BUFSIZE ;[36]
sub cnt, x2 ;[37]
sts usbInputBufOffset, cnt;[38] buffers now swapped
rjmp sendAckAndReti ;[40] 42 + 17 = 59 until SOP
handleIn:
;We don't send any data as long as the C code has not processed the current
;input data and potentially updated the output data. That's more efficient
;in terms of code size than clearing the tx buffers when a packet is received.
lds x1, usbRxLen ;[30]
cpi x1, 1 ;[32] negative values are flow control, 0 means "buffer free"
brge sendNakAndReti ;[33] unprocessed input packet?
ldi x1, USBPID_NAK ;[34] prepare value for usbTxLen
#if USB_CFG_HAVE_INTRIN_ENDPOINT
sbrc x3, 7 ;[35] x3 contains addr + endpoint
rjmp handleIn1 ;[36]
#endif
lds cnt, usbTxLen ;[37]
sbrc cnt, 4 ;[39] all handshake tokens have bit 4 set
rjmp sendCntAndReti ;[40] 42 + 16 = 58 until SOP
sts usbTxLen, x1 ;[41] x1 == USBPID_NAK from above
ldi YL, lo8(usbTxBuf) ;[43]
ldi YH, hi8(usbTxBuf) ;[44]
rjmp usbSendAndReti ;[45] 47 + 12 = 59 until SOP
; Comment about when to set usbTxLen to USBPID_NAK:
; We should set it back when we receive the ACK from the host. This would
; be simple to implement: One static variable which stores whether the last
; tx was for endpoint 0 or 1 and a compare in the receiver to distinguish the
; ACK. However, we set it back immediately when we send the package,
; assuming that no error occurs and the host sends an ACK. We save one byte
; RAM this way and avoid potential problems with endless retries. The rest of
; the driver assumes error-free transfers anyway.
#if USB_CFG_HAVE_INTRIN_ENDPOINT /* placed here due to relative jump range */
handleIn1: ;[38]
#if USB_CFG_HAVE_INTRIN_ENDPOINT3
; 2006-06-10 as suggested by O.Tamura: support second INTR IN / BULK IN endpoint
ldd x2, y+2 ;[38]
sbrc x2, 0 ;[40]
rjmp handleIn3 ;[41]
#endif
lds cnt, usbTxLen1 ;[42]
sbrc cnt, 4 ;[44] all handshake tokens have bit 4 set
rjmp sendCntAndReti ;[45] 47 + 16 = 63 until SOP
sts usbTxLen1, x1 ;[46] x1 == USBPID_NAK from above
ldi YL, lo8(usbTxBuf1) ;[48]
ldi YH, hi8(usbTxBuf1) ;[49]
rjmp usbSendAndReti ;[50] 52 + 12 + 64 until SOP
#endif
#if USB_CFG_HAVE_INTRIN_ENDPOINT && USB_CFG_HAVE_INTRIN_ENDPOINT3
handleIn3:
lds cnt, usbTxLen3 ;[43]
sbrc cnt, 4 ;[45]
rjmp sendCntAndReti ;[46] 48 + 16 = 64 until SOP
sts usbTxLen3, x1 ;[47] x1 == USBPID_NAK from above
ldi YL, lo8(usbTxBuf3) ;[49]
ldi YH, hi8(usbTxBuf3) ;[50]
rjmp usbSendAndReti ;[51] 53 + 12 = 65 until SOP
#endif
; USB spec says:
; idle = J
; J = (D+ = 0), (D- = 1)
; K = (D+ = 1), (D- = 0)
; Spec allows 7.5 bit times from EOP to SOP for replies
bitstuffN:
eor x1, x4 ;[5]
ldi x2, 0 ;[6]
nop2 ;[7]
nop ;[9]
out USBOUT, x1 ;[10] <-- out
rjmp didStuffN ;[0]
bitstuff6:
eor x1, x4 ;[4]
ldi x2, 0 ;[5]
nop2 ;[6] C is zero (brcc)
rjmp didStuff6 ;[8]
bitstuff7:
eor x1, x4 ;[3]
ldi x2, 0 ;[4]
rjmp didStuff7 ;[5]
sendNakAndReti:
ldi x3, USBPID_NAK ;[-18]
rjmp sendX3AndReti ;[-17]
sendAckAndReti:
ldi cnt, USBPID_ACK ;[-17]
sendCntAndReti:
mov x3, cnt ;[-16]
sendX3AndReti:
ldi YL, 20 ;[-15] x3==r20 address is 20
ldi YH, 0 ;[-14]
ldi cnt, 2 ;[-13]
; rjmp usbSendAndReti fallthrough
;usbSend:
;pointer to data in 'Y'
;number of bytes in 'cnt' -- including sync byte [range 2 ... 12]
;uses: x1...x4, btcnt, shift, cnt, Y
;Numbers in brackets are time since first bit of sync pattern is sent
;We don't match the transfer rate exactly (don't insert leap cycles every third
;byte) because the spec demands only 1.5% precision anyway.
usbSendAndReti: ; 12 cycles until SOP
in x2, USBDDR ;[-12]
ori x2, USBMASK ;[-11]
sbi USBOUT, USBMINUS;[-10] prepare idle state; D+ and D- must have been 0 (no pullups)
in x1, USBOUT ;[-8] port mirror for tx loop
out USBDDR, x2 ;[-7] <- acquire bus
; need not init x2 (bitstuff history) because sync starts with 0
ldi x4, USBMASK ;[-6] exor mask
ldi shift, 0x80 ;[-5] sync byte is first byte sent
txByteLoop:
ldi bitcnt, 0x2a ;[-4] [6] binary 00101010
txBitLoop:
sbrs shift, 0 ;[-3] [7]
eor x1, x4 ;[-2] [8]
out USBOUT, x1 ;[-1] [9] <-- out N
ror shift ;[0] [10]
ror x2 ;[1]
didStuffN:
cpi x2, 0xfc ;[2]
brcc bitstuffN ;[3]
lsr bitcnt ;[4]
brcc txBitLoop ;[5]
brne txBitLoop ;[6]
sbrs shift, 0 ;[7]
eor x1, x4 ;[8]
ror shift ;[9]
didStuff6:
out USBOUT, x1 ;[-1] [10] <-- out 6
ror x2 ;[0] [11]
cpi x2, 0xfc ;[1]
brcc bitstuff6 ;[2]
sbrs shift, 0 ;[3]
eor x1, x4 ;[4]
ror shift ;[5]
ror x2 ;[6]
didStuff7:
nop ;[7]
nop2 ;[8]
out USBOUT, x1 ;[-1][10] <-- out 7
cpi x2, 0xfc ;[0] [11]
brcc bitstuff7 ;[1]
ld shift, y+ ;[2]
dec cnt ;[4]
brne txByteLoop ;[4]
;make SE0:
cbr x1, USBMASK ;[7] prepare SE0 [spec says EOP may be 21 to 25 cycles]
lds x2, usbNewDeviceAddr;[8]
out USBOUT, x1 ;[10] <-- out SE0 -- from now 2 bits = 22 cycles until bus idle
;2006-03-06: moved transfer of new address to usbDeviceAddr from C-Code to asm:
;set address only after data packet was sent, not after handshake
subi YL, 2 ;[0]
sbci YH, 0 ;[1]
breq skipAddrAssign ;[2]
sts usbDeviceAddr, x2; if not skipped: SE0 is one cycle longer
skipAddrAssign:
;end of usbDeviceAddress transfer
ldi x2, 1<<USB_INTR_PENDING_BIT;[4] int0 occurred during TX -- clear pending flag
USB_STORE_PENDING(x2) ;[5]
ori x1, USBIDLE ;[6]
in x2, USBDDR ;[7]
cbr x2, USBMASK ;[8] set both pins to input
mov x3, x1 ;[9]
cbr x3, USBMASK ;[10] configure no pullup on both pins
ldi x4, 4 ;[11]
se0Delay:
dec x4 ;[12] [15] [18] [21]
brne se0Delay ;[13] [16] [19] [22]
out USBOUT, x1 ;[23] <-- out J (idle) -- end of SE0 (EOP signal)
out USBDDR, x2 ;[24] <-- release bus now
out USBOUT, x3 ;[25] <-- ensure no pull-up resistors are active
rjmp doReturn

580
usbdrv/usbdrvasm165.S Normal file
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@ -0,0 +1,580 @@
/* Name: usbdrvasm165.S
* Project: AVR USB driver
* Author: Christian Starkjohann
* Creation Date: 2007-04-22
* Tabsize: 4
* Copyright: (c) 2007 by OBJECTIVE DEVELOPMENT Software GmbH
* License: GNU GPL v2 (see License.txt) or proprietary (CommercialLicense.txt)
* Revision: $Id: usbdrvasm165.S,v 1.1 2013-04-25 02:18:15 cvs Exp $
*/
/* Do not link this file! Link usbdrvasm.S instead, which includes the
* appropriate implementation!
*/
/*
General Description:
This file is the 16.5 MHz version of the USB driver. It is intended for the
ATTiny45 and similar controllers running on 16.5 MHz internal RC oscillator.
This version contains a phase locked loop in the receiver routine to cope with
slight clock rate deviations of up to +/- 1%.
See usbdrv.h for a description of the entire driver.
Since almost all of this code is timing critical, don't change unless you
really know what you are doing! Many parts require not only a maximum number
of CPU cycles, but even an exact number of cycles!
*/
;Software-receiver engine. Strict timing! Don't change unless you can preserve timing!
;interrupt response time: 4 cycles + insn running = 7 max if interrupts always enabled
;max allowable interrupt latency: 59 cycles -> max 52 cycles interrupt disable
;max stack usage: [ret(2), r0, SREG, YL, YH, shift, x1, x2, x3, x4, cnt] = 12 bytes
;nominal frequency: 16.5 MHz -> 11 cycles per bit
; 16.3125 MHz < F_CPU < 16.6875 MHz (+/- 1.1%)
; Numbers in brackets are clocks counted from center of last sync bit
; when instruction starts
USB_INTR_VECTOR:
;order of registers pushed: r0, SREG [sofError], YL, YH, shift, x1, x2, x3, x4, cnt
push r0 ;[-23] push only what is necessary to sync with edge ASAP
in r0, SREG ;[-21]
push r0 ;[-20]
;----------------------------------------------------------------------------
; Synchronize with sync pattern:
;----------------------------------------------------------------------------
;sync byte (D-) pattern LSb to MSb: 01010100 [1 = idle = J, 0 = K]
;sync up with J to K edge during sync pattern -- use fastest possible loops
;first part has no timeout because it waits for IDLE or SE1 (== disconnected)
waitForJ:
sbis USBIN, USBMINUS ;[-18] wait for D- == 1
rjmp waitForJ
waitForK:
;The following code results in a sampling window of < 1/4 bit which meets the spec.
sbis USBIN, USBMINUS ;[-15]
rjmp foundK ;[-14]
sbis USBIN, USBMINUS
rjmp foundK
sbis USBIN, USBMINUS
rjmp foundK
sbis USBIN, USBMINUS
rjmp foundK
sbis USBIN, USBMINUS
rjmp foundK
sbis USBIN, USBMINUS
rjmp foundK
#if USB_COUNT_SOF
lds YL, usbSofCount
inc YL
sts usbSofCount, YL
#endif /* USB_COUNT_SOF */
rjmp sofError
foundK: ;[-12]
;{3, 5} after falling D- edge, average delay: 4 cycles [we want 5 for center sampling]
;we have 1 bit time for setup purposes, then sample again. Numbers in brackets
;are cycles from center of first sync (double K) bit after the instruction
push YL ;[-12]
; [---] ;[-11]
push YH ;[-10]
; [---] ;[-9]
lds YL, usbInputBufOffset;[-8]
; [---] ;[-7]
clr YH ;[-6]
subi YL, lo8(-(usbRxBuf));[-5] [rx loop init]
sbci YH, hi8(-(usbRxBuf));[-4] [rx loop init]
mov r0, x2 ;[-3] [rx loop init]
sbis USBIN, USBMINUS ;[-2] we want two bits K (sample 2 cycles too early)
rjmp haveTwoBitsK ;[-1]
pop YH ;[0] undo the pushes from before
pop YL ;[2]
rjmp waitForK ;[4] this was not the end of sync, retry
; The entire loop from waitForK until rjmp waitForK above must not exceed two
; bit times (= 22 cycles).
;----------------------------------------------------------------------------
; push more registers and initialize values while we sample the first bits:
;----------------------------------------------------------------------------
haveTwoBitsK: ;[1]
push shift ;[1]
push x1 ;[3]
push x2 ;[5]
push x3 ;[7]
ldi shift, 0xff ;[9] [rx loop init]
ori x3, 0xff ;[10] [rx loop init] == ser x3, clear zero flag
in x1, USBIN ;[11] <-- sample bit 0
bst x1, USBMINUS ;[12]
bld shift, 0 ;[13]
push x4 ;[14] == phase
; [---] ;[15]
push cnt ;[16]
; [---] ;[17]
ldi phase, 0 ;[18] [rx loop init]
ldi cnt, USB_BUFSIZE;[19] [rx loop init]
rjmp rxbit1 ;[20]
; [---] ;[21]
;----------------------------------------------------------------------------
; Receiver loop (numbers in brackets are cycles within byte after instr)
;----------------------------------------------------------------------------
/*
byte oriented operations done during loop:
bit 0: store data
bit 1: SE0 check
bit 2: overflow check
bit 3: catch up
bit 4: rjmp to achieve conditional jump range
bit 5: PLL
bit 6: catch up
bit 7: jump, fixup bitstuff
; 87 [+ 2] cycles
------------------------------------------------------------------
*/
continueWithBit5:
in x2, USBIN ;[055] <-- bit 5
eor r0, x2 ;[056]
or phase, r0 ;[057]
sbrc phase, USBMINUS ;[058]
lpm ;[059] optional nop3; modifies r0
in phase, USBIN ;[060] <-- phase
eor x1, x2 ;[061]
bst x1, USBMINUS ;[062]
bld shift, 5 ;[063]
andi shift, 0x3f ;[064]
in x1, USBIN ;[065] <-- bit 6
breq unstuff5 ;[066] *** unstuff escape
eor phase, x1 ;[067]
eor x2, x1 ;[068]
bst x2, USBMINUS ;[069]
bld shift, 6 ;[070]
didUnstuff6: ;[ ]
in r0, USBIN ;[071] <-- phase
cpi shift, 0x02 ;[072]
brlo unstuff6 ;[073] *** unstuff escape
didUnstuff5: ;[ ]
nop2 ;[074]
; [---] ;[075]
in x2, USBIN ;[076] <-- bit 7
eor x1, x2 ;[077]
bst x1, USBMINUS ;[078]
bld shift, 7 ;[079]
didUnstuff7: ;[ ]
eor r0, x2 ;[080]
or phase, r0 ;[081]
in r0, USBIN ;[082] <-- phase
cpi shift, 0x04 ;[083]
brsh rxLoop ;[084]
; [---] ;[085]
unstuff7: ;[ ]
andi x3, ~0x80 ;[085]
ori shift, 0x80 ;[086]
in x2, USBIN ;[087] <-- sample stuffed bit 7
nop ;[088]
rjmp didUnstuff7 ;[089]
; [---] ;[090]
;[080]
unstuff5: ;[067]
eor phase, x1 ;[068]
andi x3, ~0x20 ;[069]
ori shift, 0x20 ;[070]
in r0, USBIN ;[071] <-- phase
mov x2, x1 ;[072]
nop ;[073]
nop2 ;[074]
; [---] ;[075]
in x1, USBIN ;[076] <-- bit 6
eor r0, x1 ;[077]
or phase, r0 ;[078]
eor x2, x1 ;[079]
bst x2, USBMINUS ;[080]
bld shift, 6 ;[081] no need to check bitstuffing, we just had one
in r0, USBIN ;[082] <-- phase
rjmp didUnstuff5 ;[083]
; [---] ;[084]
;[074]
unstuff6: ;[074]
andi x3, ~0x40 ;[075]
in x1, USBIN ;[076] <-- bit 6 again
ori shift, 0x40 ;[077]
nop2 ;[078]
; [---] ;[079]
rjmp didUnstuff6 ;[080]
; [---] ;[081]
;[071]
unstuff0: ;[013]
eor r0, x2 ;[014]
or phase, r0 ;[015]
andi x2, USBMASK ;[016] check for SE0
in r0, USBIN ;[017] <-- phase
breq didUnstuff0 ;[018] direct jump to se0 would be too long
andi x3, ~0x01 ;[019]
ori shift, 0x01 ;[020]
mov x1, x2 ;[021] mov existing sample
in x2, USBIN ;[022] <-- bit 1 again
rjmp didUnstuff0 ;[023]
; [---] ;[024]
;[014]
unstuff1: ;[024]
eor r0, x1 ;[025]
or phase, r0 ;[026]
andi x3, ~0x02 ;[027]
in r0, USBIN ;[028] <-- phase
ori shift, 0x02 ;[029]
mov x2, x1 ;[030]
rjmp didUnstuff1 ;[031]
; [---] ;[032]
;[022]
unstuff2: ;[035]
eor r0, x2 ;[036]
or phase, r0 ;[037]
andi x3, ~0x04 ;[038]
in r0, USBIN ;[039] <-- phase
ori shift, 0x04 ;[040]
mov x1, x2 ;[041]
rjmp didUnstuff2 ;[042]
; [---] ;[043]
;[033]
unstuff3: ;[043]
in x2, USBIN ;[044] <-- bit 3 again
eor r0, x2 ;[045]
or phase, r0 ;[046]
andi x3, ~0x08 ;[047]
ori shift, 0x08 ;[048]
nop ;[049]
in r0, USBIN ;[050] <-- phase
rjmp didUnstuff3 ;[051]
; [---] ;[052]
;[042]
unstuff4: ;[053]
andi x3, ~0x10 ;[054]
in x1, USBIN ;[055] <-- bit 4 again
ori shift, 0x10 ;[056]
rjmp didUnstuff4 ;[057]
; [---] ;[058]
;[048]
rxLoop: ;[085]
eor x3, shift ;[086] reconstruct: x3 is 0 at bit locations we changed, 1 at others
in x1, USBIN ;[000] <-- bit 0
st y+, x3 ;[001]
; [---] ;[002]
eor r0, x1 ;[003]
or phase, r0 ;[004]
eor x2, x1 ;[005]
in r0, USBIN ;[006] <-- phase
ser x3 ;[007]
bst x2, USBMINUS ;[008]
bld shift, 0 ;[009]
andi shift, 0xf9 ;[010]
rxbit1: ;[ ]
in x2, USBIN ;[011] <-- bit 1
breq unstuff0 ;[012] *** unstuff escape
andi x2, USBMASK ;[013] SE0 check for bit 1
didUnstuff0: ;[ ] Z only set if we detected SE0 in bitstuff
breq se0 ;[014]
eor r0, x2 ;[015]
or phase, r0 ;[016]
in r0, USBIN ;[017] <-- phase
eor x1, x2 ;[018]
bst x1, USBMINUS ;[019]
bld shift, 1 ;[020]
andi shift, 0xf3 ;[021]
didUnstuff1: ;[ ]
in x1, USBIN ;[022] <-- bit 2
breq unstuff1 ;[023] *** unstuff escape
eor r0, x1 ;[024]
or phase, r0 ;[025]
subi cnt, 1 ;[026] overflow check
brcs overflow ;[027]
in r0, USBIN ;[028] <-- phase
eor x2, x1 ;[029]
bst x2, USBMINUS ;[030]
bld shift, 2 ;[031]
andi shift, 0xe7 ;[032]
didUnstuff2: ;[ ]
in x2, USBIN ;[033] <-- bit 3
breq unstuff2 ;[034] *** unstuff escape
eor r0, x2 ;[035]
or phase, r0 ;[036]
eor x1, x2 ;[037]
bst x1, USBMINUS ;[038]
in r0, USBIN ;[039] <-- phase
bld shift, 3 ;[040]
andi shift, 0xcf ;[041]
didUnstuff3: ;[ ]
breq unstuff3 ;[042] *** unstuff escape
nop ;[043]
in x1, USBIN ;[044] <-- bit 4
eor x2, x1 ;[045]
bst x2, USBMINUS ;[046]
bld shift, 4 ;[047]
didUnstuff4: ;[ ]
eor r0, x1 ;[048]
or phase, r0 ;[049]
in r0, USBIN ;[050] <-- phase
andi shift, 0x9f ;[051]
breq unstuff4 ;[052] *** unstuff escape
rjmp continueWithBit5;[053]
; [---] ;[054]
;----------------------------------------------------------------------------
; Processing of received packet (numbers in brackets are cycles after center of SE0)
;----------------------------------------------------------------------------
;This is the only non-error exit point for the software receiver loop
;we don't check any CRCs here because there is no time left.
#define token x1
se0:
subi cnt, USB_BUFSIZE ;[5]
neg cnt ;[6]
cpi cnt, 3 ;[7]
ldi x2, 1<<USB_INTR_PENDING_BIT ;[8]
USB_STORE_PENDING(x2) ;[9] clear pending intr and check flag later. SE0 should be over.
brlo doReturn ;[10] this is probably an ACK, NAK or similar packet
sub YL, cnt ;[11]
sbci YH, 0 ;[12]
ld token, y ;[13]
cpi token, USBPID_DATA0 ;[15]
breq handleData ;[16]
cpi token, USBPID_DATA1 ;[17]
breq handleData ;[18]
ldd x2, y+1 ;[19] ADDR and 1 bit endpoint number
mov x3, x2 ;[21] store for endpoint number
andi x2, 0x7f ;[22] x2 is now ADDR
lds shift, usbDeviceAddr;[23]
cp x2, shift ;[25]
overflow: ; This is a hack: brcs overflow will never have Z flag set
brne ignorePacket ;[26] packet for different address
cpi token, USBPID_IN ;[27]
breq handleIn ;[28]
cpi token, USBPID_SETUP ;[29]
breq handleSetupOrOut ;[30]
cpi token, USBPID_OUT ;[31]
breq handleSetupOrOut ;[32]
; rjmp ignorePacket ;fallthrough, should not happen anyway.
ignorePacket:
clr shift
sts usbCurrentTok, shift
doReturn:
pop cnt
pop x4
pop x3
pop x2
pop x1
pop shift
pop YH
pop YL
sofError:
pop r0
out SREG, r0
pop r0
reti
#if USB_CFG_HAVE_INTRIN_ENDPOINT && USB_CFG_HAVE_INTRIN_ENDPOINT3
handleIn3:
lds cnt, usbTxLen3 ;[43]
sbrc cnt, 4 ;[45]
rjmp sendCntAndReti ;[46] 48 + 16 = 64 until SOP
sts usbTxLen3, x1 ;[47] x1 == USBPID_NAK from above
ldi YL, lo8(usbTxBuf3) ;[49]
ldi YH, hi8(usbTxBuf3) ;[50]
rjmp usbSendAndReti ;[51] 53 + 12 = 65 until SOP
#endif
;Setup and Out are followed by a data packet two bit times (16 cycles) after
;the end of SE0. The sync code allows up to 40 cycles delay from the start of
;the sync pattern until the first bit is sampled. That's a total of 56 cycles.
handleSetupOrOut: ;[34]
#if USB_CFG_IMPLEMENT_FN_WRITEOUT /* if we have data for second OUT endpoint, set usbCurrentTok to -1 */
sbrc x3, 7 ;[34] skip if endpoint 0
ldi token, -1 ;[35] indicate that this is endpoint 1 OUT
#endif
sts usbCurrentTok, token;[36]
pop cnt ;[38]
pop x4 ;[40]
pop x3 ;[42]
pop x2 ;[44]
pop x1 ;[46]
pop shift ;[48]
pop YH ;[50]
pop YL ;[52]
USB_LOAD_PENDING(r0) ;[54]
sbrc r0, USB_INTR_PENDING_BIT;[55] check whether data is already arriving
rjmp waitForJ ;[56] save the pops and pushes -- a new interrupt is aready pending
rjmp sofError ;[57] not an error, but it does the pops and reti we want
handleData:
lds token, usbCurrentTok;[20]
tst token ;[22]
breq doReturn ;[23]
lds x2, usbRxLen ;[24]
tst x2 ;[26]
brne sendNakAndReti ;[27]
; 2006-03-11: The following two lines fix a problem where the device was not
; recognized if usbPoll() was called less frequently than once every 4 ms.
cpi cnt, 4 ;[28] zero sized data packets are status phase only -- ignore and ack
brmi sendAckAndReti ;[29] keep rx buffer clean -- we must not NAK next SETUP
sts usbRxLen, cnt ;[30] store received data, swap buffers
sts usbRxToken, token ;[32]
lds x2, usbInputBufOffset;[34] swap buffers
ldi cnt, USB_BUFSIZE ;[36]
sub cnt, x2 ;[37]
sts usbInputBufOffset, cnt;[38] buffers now swapped
rjmp sendAckAndReti ;[40] 42 + 17 = 59 until SOP
handleIn:
;We don't send any data as long as the C code has not processed the current
;input data and potentially updated the output data. That's more efficient
;in terms of code size than clearing the tx buffers when a packet is received.
lds x1, usbRxLen ;[30]
cpi x1, 1 ;[32] negative values are flow control, 0 means "buffer free"
brge sendNakAndReti ;[33] unprocessed input packet?
ldi x1, USBPID_NAK ;[34] prepare value for usbTxLen
#if USB_CFG_HAVE_INTRIN_ENDPOINT
sbrc x3, 7 ;[35] x3 contains addr + endpoint
rjmp handleIn1 ;[36]
#endif
lds cnt, usbTxLen ;[37]
sbrc cnt, 4 ;[39] all handshake tokens have bit 4 set
rjmp sendCntAndReti ;[40] 42 + 16 = 58 until SOP
sts usbTxLen, x1 ;[41] x1 == USBPID_NAK from above
ldi YL, lo8(usbTxBuf) ;[43]
ldi YH, hi8(usbTxBuf) ;[44]
rjmp usbSendAndReti ;[45] 47 + 12 = 59 until SOP
; Comment about when to set usbTxLen to USBPID_NAK:
; We should set it back when we receive the ACK from the host. This would
; be simple to implement: One static variable which stores whether the last
; tx was for endpoint 0 or 1 and a compare in the receiver to distinguish the
; ACK. However, we set it back immediately when we send the package,
; assuming that no error occurs and the host sends an ACK. We save one byte
; RAM this way and avoid potential problems with endless retries. The rest of
; the driver assumes error-free transfers anyway.
#if USB_CFG_HAVE_INTRIN_ENDPOINT /* placed here due to relative jump range */
handleIn1: ;[38]
#if USB_CFG_HAVE_INTRIN_ENDPOINT3
; 2006-06-10 as suggested by O.Tamura: support second INTR IN / BULK IN endpoint
ldd x2, y+2 ;[38]
sbrc x2, 0 ;[40]
rjmp handleIn3 ;[41]
#endif
lds cnt, usbTxLen1 ;[42]
sbrc cnt, 4 ;[44] all handshake tokens have bit 4 set
rjmp sendCntAndReti ;[45] 47 + 16 = 63 until SOP
sts usbTxLen1, x1 ;[46] x1 == USBPID_NAK from above
ldi YL, lo8(usbTxBuf1) ;[48]
ldi YH, hi8(usbTxBuf1) ;[49]
rjmp usbSendAndReti ;[50] 52 + 12 + 64 until SOP
#endif
; USB spec says:
; idle = J
; J = (D+ = 0), (D- = 1)
; K = (D+ = 1), (D- = 0)
; Spec allows 7.5 bit times from EOP to SOP for replies
bitstuff7:
eor x1, x4 ;[4]
ldi x2, 0 ;[5]
nop2 ;[6] C is zero (brcc)
rjmp didStuff7 ;[8]
bitstuffN:
eor x1, x4 ;[5]
ldi x2, 0 ;[6]
lpm ;[7] 3 cycle NOP, modifies r0
out USBOUT, x1 ;[10] <-- out
rjmp didStuffN ;[0]
#define bitStatus x3
sendNakAndReti:
ldi cnt, USBPID_NAK ;[-19]
rjmp sendCntAndReti ;[-18]
sendAckAndReti:
ldi cnt, USBPID_ACK ;[-17]
sendCntAndReti:
mov r0, cnt ;[-16]
ldi YL, 0 ;[-15] R0 address is 0
ldi YH, 0 ;[-14]
ldi cnt, 2 ;[-13]
; rjmp usbSendAndReti fallthrough
;usbSend:
;pointer to data in 'Y'
;number of bytes in 'cnt' -- including sync byte [range 2 ... 12]
;uses: x1...x4, shift, cnt, Y
;Numbers in brackets are time since first bit of sync pattern is sent
usbSendAndReti: ; 12 cycles until SOP
in x2, USBDDR ;[-12]
ori x2, USBMASK ;[-11]
sbi USBOUT, USBMINUS;[-10] prepare idle state; D+ and D- must have been 0 (no pullups)
in x1, USBOUT ;[-8] port mirror for tx loop
out USBDDR, x2 ;[-7] <- acquire bus
; need not init x2 (bitstuff history) because sync starts with 0
ldi x4, USBMASK ;[-6] exor mask
ldi shift, 0x80 ;[-5] sync byte is first byte sent
ldi bitStatus, 0xff ;[-4] init bit loop counter, works for up to 12 bytes
byteloop:
bitloop:
sbrs shift, 0 ;[8] [-3]
eor x1, x4 ;[9] [-2]
out USBOUT, x1 ;[10] [-1] <-- out
ror shift ;[0]
ror x2 ;[1]
didStuffN:
cpi x2, 0xfc ;[2]
brcc bitstuffN ;[3]
nop ;[4]
subi bitStatus, 37 ;[5] 256 / 7 ~=~ 37
brcc bitloop ;[6] when we leave the loop, bitStatus has almost the initial value
sbrs shift, 0 ;[7]
eor x1, x4 ;[8]
ror shift ;[9]
didStuff7:
out USBOUT, x1 ;[10] <-- out
ror x2 ;[0]
cpi x2, 0xfc ;[1]
brcc bitstuff7 ;[2]
ld shift, y+ ;[3]
dec cnt ;[5]
brne byteloop ;[6]
;make SE0:
cbr x1, USBMASK ;[7] prepare SE0 [spec says EOP may be 21 to 25 cycles]
lds x2, usbNewDeviceAddr;[8]
out USBOUT, x1 ;[10] <-- out SE0 -- from now 2 bits = 22 cycles until bus idle
;2006-03-06: moved transfer of new address to usbDeviceAddr from C-Code to asm:
;set address only after data packet was sent, not after handshake
subi YL, 2 ;[0]
sbci YH, 0 ;[1]
breq skipAddrAssign ;[2]
sts usbDeviceAddr, x2; if not skipped: SE0 is one cycle longer
skipAddrAssign:
;end of usbDeviceAddress transfer
ldi x2, 1<<USB_INTR_PENDING_BIT;[4] int0 occurred during TX -- clear pending flag
USB_STORE_PENDING(x2) ;[5]
ori x1, USBIDLE ;[6]
in x2, USBDDR ;[7]
cbr x2, USBMASK ;[8] set both pins to input
mov x3, x1 ;[9]
cbr x3, USBMASK ;[10] configure no pullup on both pins
ldi x4, 4 ;[11]
se0Delay:
dec x4 ;[12] [15] [18] [21]
brne se0Delay ;[13] [16] [19] [22]
out USBOUT, x1 ;[23] <-- out J (idle) -- end of SE0 (EOP signal)
out USBDDR, x2 ;[24] <-- release bus now
out USBOUT, x3 ;[25] <-- ensure no pull-up resistors are active
rjmp doReturn