diff --git a/usbdrv/CommercialLicense.txt b/usbdrv/CommercialLicense.txt new file mode 100644 index 0000000..240e45f --- /dev/null +++ b/usbdrv/CommercialLicense.txt @@ -0,0 +1,155 @@ +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. + diff --git a/usbdrv/usbconfig-prototype.h b/usbdrv/usbconfig-prototype.h new file mode 100644 index 0000000..7ddd113 --- /dev/null +++ b/usbdrv/usbconfig-prototype.h @@ -0,0 +1,274 @@ +/* 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__ */ diff --git a/usbdrv/usbdrvasm12.S b/usbdrv/usbdrvasm12.S new file mode 100644 index 0000000..8c2135f --- /dev/null +++ b/usbdrv/usbdrvasm12.S @@ -0,0 +1,561 @@ +/* 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< 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< 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< 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<