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https://github.com/raphnet/dreamcast_usb
synced 2024-12-21 22:58:52 -05:00
Fix floating pins bug, improve debug switches
This commit is contained in:
Raphaël Assénat
parent
1f9db3fdb4
commit
c1181687a7
71
maplebus.c
71
maplebus.c
@ -21,6 +21,11 @@
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#include <util/delay.h>
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#include "usbdrv.h"
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#undef NOLRC
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#undef TRACE_RX_START_END
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#undef TRACE_DECODED
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#undef TRACE_PIN1_BITS
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//
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//
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// PORTC0 : Pin 1
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@ -29,10 +34,14 @@
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void maple_init(void)
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{
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DDRC &= ~0x03;
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DDRC = 0xFC;
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PORTC = 0x03;
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}
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#define transmitMode() do { PORTC |= 0x03; DDRC |= 0x03; } while(0)
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#define inputMode() do { PORTC |= 0x03; DDRC &= ~0x03; } while(0)
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#define MAPLE_BUF_SIZE 640
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#define MAPLE_BUF_SIZE 641
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static unsigned char maplebuf[MAPLE_BUF_SIZE];
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static unsigned char buf_used;
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static unsigned char buf_phase;
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@ -47,6 +56,8 @@ static void buf_reset(void)
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static void buf_addBit(char value)
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{
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// The values in maplebuf will be written
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// directly to PORTC. Unused bits will be low.
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if (buf_phase & 0x01) {
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maplebuf[buf_used] = PIN_5;
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if (value) {
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@ -72,6 +83,15 @@ static int maplebus_decode(unsigned char *data, unsigned int maxlen)
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unsigned char last_fell;
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int i;
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#ifdef TRACE_DECODED
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PORTB |= 0x10;
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PORTB &= ~0x10;
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PORTB |= 0x10;
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PORTB &= ~0x10;
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PORTB |= 0x10;
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PORTB &= ~0x10;
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#endif
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// Look for the initial phase 1 (Pin 1 high, Pin 5 low). This
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// is to skip what we got of the sync/start of frame sequence.
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//
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@ -90,7 +110,15 @@ static int maplebus_decode(unsigned char *data, unsigned int maxlen)
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last_fell = 0;
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for (; i<MAPLE_BUF_SIZE; i++) {
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unsigned char fell;
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unsigned char cur = maplebuf[i];
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unsigned char cur = maplebuf[i] & 0x3;
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#ifdef TRACE_PIN1_BITS
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if (cur & 1) {
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PORTB |= 0x10;
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} else {
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PORTB &= ~0x10;
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}
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#endif
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if (cur == last) {
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continue; // no change
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@ -106,8 +134,14 @@ static int maplebus_decode(unsigned char *data, unsigned int maxlen)
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if (fell == last_fell) {
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// two identical consecutive phases marks the end of the packet.
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#ifdef TRACE_DECODED
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PORTB |= 0x10;
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PORTB &= ~0x10;
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PORTB |= 0x10;
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PORTB &= ~0x10;
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PORTB |= 0x10;
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PORTB &= ~0x10;
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#endif
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break;
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}
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@ -122,8 +156,14 @@ static int maplebus_decode(unsigned char *data, unsigned int maxlen)
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if (cur) {
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data[dst_pos] |= dst_b;
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#ifdef TRACE_DECODED
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PORTB |= 0x10;
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#endif
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}
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else {
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#ifdef TRACE_DECODED
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PORTB &= ~0x10;
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#endif
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}
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}
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@ -138,6 +178,10 @@ static int maplebus_decode(unsigned char *data, unsigned int maxlen)
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last = cur;
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}
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#ifdef TRACE_DECODED
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PORTB &= ~0x10;
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#endif
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return dst_pos;
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}
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@ -167,8 +211,8 @@ int maple_receivePacket(unsigned char *data, unsigned int maxlen)
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" push r31 \n" // 2
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" clr %1 \n" // 1 (result=0, no timeout)
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" sbi 0x5, 4 \n" // PB4
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" cbi 0x5, 4 \n"
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// " sbi 0x5, 4 \n" // PB4
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// " cbi 0x5, 4 \n"
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// Loop until a change is detected.
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" ldi r18, 255 \n"
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@ -188,16 +232,20 @@ int maple_receivePacket(unsigned char *data, unsigned int maxlen)
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" jmp done \n"
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"start_rx: \n"
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#ifdef TRACE_RX_START_END
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" sbi 0x5, 4 \n" // PB4
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" cbi 0x5, 4 \n"
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#endif
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// We will loose the first bit(s), but
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// it's only the start of frame.
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#include "rxcode.asm"
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"done:\n"
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#ifdef TRACE_RX_START_END
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" sbi 0x5, 4 \n" // PB4
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" cbi 0x5, 4 \n"
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#endif
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" pop r31 \n" // 2
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" pop r30 \n" // 2
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: "=z"(tmp), "=r"(timeout)
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@ -211,16 +259,18 @@ int maple_receivePacket(unsigned char *data, unsigned int maxlen)
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if (res<=0)
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return res;
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// A packet containts n groups of 4 bytes, plus 1 byte crc.
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// A packet contains n groups of 4 bytes, plus 1 byte crc.
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if (((res-1) & 0x3) != 0) {
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return -2; // frame error
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}
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#ifndef NOLRC
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for (lrc=0, i=0; i<res; i++) {
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lrc ^= data[i];
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}
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if (lrc)
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return -2; // LRC error
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#endif
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/* Reverse each group of 4 bytes */
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for (i=0; i<(res-1); i+=4) {
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@ -252,8 +302,7 @@ void maple_sendPacket(unsigned char *data, unsigned char len)
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}
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// Output
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PORTC |= 0x03;
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DDRC |= 0x03;
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transmitMode();
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// DC controller pin 1 and pin 5
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#define SET_1 " sbi %0, 0\n"
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@ -286,14 +335,14 @@ void maple_sendPacket(unsigned char *data, unsigned char len)
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"next_byte:\n"
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"out %0, r20 \n" // 1 initial phase 1 state
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"nop \n" // 1
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"out %0, r16 \n" // 1 data
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"cbi %0, 0 \n" // 1 falling edge on pin 1
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"ld r16, z+ \n" // 2 load phase 2 data
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"nop \n" // 1
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"nop \n" // 1
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"nop \n" // 1
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"out %0, r21 \n" // 1 initial phase 2 state
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"nop \n"
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"out %0, r16 \n" // 1 data
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"cbi %0, 1 \n" // 1 falling edge on pin 5
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"ld r16, z+ \n" // 2
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@ -314,7 +363,7 @@ void maple_sendPacket(unsigned char *data, unsigned char len)
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);
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// back to input to receive the answer
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DDRC &= ~0x03;
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inputMode();
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}
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