- switch(Uart.state) {
- case STATE_UNSYNCD:
- LED_A_OFF();
- if(!bit) {
- // we went low, so this could be the beginning
- // of an SOF
- Uart.state = STATE_GOT_FALLING_EDGE_OF_SOF;
- Uart.posCnt = 0;
- Uart.bitCnt = 0;
- }
- break;
-
- case STATE_GOT_FALLING_EDGE_OF_SOF:
- Uart.posCnt++;
- if(Uart.posCnt == 2) {
- if(bit) {
- if(Uart.bitCnt >= 10) {
- // we've seen enough consecutive
- // zeros that it's a valid SOF
- Uart.posCnt = 0;
- Uart.byteCnt = 0;
- Uart.state = STATE_AWAITING_START_BIT;
- LED_A_ON(); // Indicate we got a valid SOF
- } else {
- // didn't stay down long enough
- // before going high, error
- Uart.state = STATE_ERROR_WAIT;
- }
- } else {
- // do nothing, keep waiting
- }
- Uart.bitCnt++;
- }
- if(Uart.posCnt >= 4) Uart.posCnt = 0;
- if(Uart.bitCnt > 14) {
- // Give up if we see too many zeros without
- // a one, too.
- Uart.state = STATE_ERROR_WAIT;
- }
- break;
-
- case STATE_AWAITING_START_BIT:
- Uart.posCnt++;
- if(bit) {
- if(Uart.posCnt > 25) {
- // stayed high for too long between
- // characters, error
- Uart.state = STATE_ERROR_WAIT;
- }
- } else {
- // falling edge, this starts the data byte
- Uart.posCnt = 0;
- Uart.bitCnt = 0;
- Uart.shiftReg = 0;
- Uart.state = STATE_RECEIVING_DATA;
- LED_A_ON(); // Indicate we're receiving
- }
- break;
-
- case STATE_RECEIVING_DATA:
- Uart.posCnt++;
- if(Uart.posCnt == 2) {
- // time to sample a bit
- Uart.shiftReg >>= 1;
- if(bit) {
- Uart.shiftReg |= 0x200;
- }
- Uart.bitCnt++;
- }
- if(Uart.posCnt >= 4) {
- Uart.posCnt = 0;
- }
- if(Uart.bitCnt == 10) {
- if((Uart.shiftReg & 0x200) && !(Uart.shiftReg & 0x001))
- {
- // this is a data byte, with correct
- // start and stop bits
- Uart.output[Uart.byteCnt] = (Uart.shiftReg >> 1) & 0xff;
- Uart.byteCnt++;
-
- if(Uart.byteCnt >= Uart.byteCntMax) {
- // Buffer overflowed, give up
- Uart.posCnt = 0;
- Uart.state = STATE_ERROR_WAIT;
- } else {
- // so get the next byte now
- Uart.posCnt = 0;
- Uart.state = STATE_AWAITING_START_BIT;
- }
- } else if(Uart.shiftReg == 0x000) {
- // this is an EOF byte
- LED_A_OFF(); // Finished receiving
- return TRUE;
- } else {
- // this is an error
- Uart.posCnt = 0;
- Uart.state = STATE_ERROR_WAIT;
- }
- }
- break;
-
- case STATE_ERROR_WAIT:
- // We're all screwed up, so wait a little while
- // for whatever went wrong to finish, and then
- // start over.
- Uart.posCnt++;
- if(Uart.posCnt > 10) {
- Uart.state = STATE_UNSYNCD;
- }
- break;
-
- default:
- Uart.state = STATE_UNSYNCD;
- break;
- }
-
- // This row make the error blew circular buffer in hf 14b snoop
- //if (Uart.state == STATE_ERROR_WAIT) LED_A_OFF(); // Error
-
- return FALSE;
+ switch(Uart.state) {
+ case STATE_UNSYNCD:
+ LED_A_OFF();
+ if(!bit) {
+ // we went low, so this could be the beginning
+ // of an SOF
+ Uart.state = STATE_GOT_FALLING_EDGE_OF_SOF;
+ Uart.posCnt = 0;
+ Uart.bitCnt = 0;
+ }
+ break;
+
+ case STATE_GOT_FALLING_EDGE_OF_SOF:
+ Uart.posCnt++;
+ if(Uart.posCnt == 2) {
+ if(bit) {
+ if(Uart.bitCnt >= 10) {
+ // we've seen enough consecutive
+ // zeros that it's a valid SOF
+ Uart.posCnt = 0;
+ Uart.byteCnt = 0;
+ Uart.state = STATE_AWAITING_START_BIT;
+ LED_A_ON(); // Indicate we got a valid SOF
+ } else {
+ // didn't stay down long enough
+ // before going high, error
+ Uart.state = STATE_ERROR_WAIT;
+ }
+ } else {
+ // do nothing, keep waiting
+ }
+ Uart.bitCnt++;
+ }
+ if(Uart.posCnt >= 4) Uart.posCnt = 0;
+ if(Uart.bitCnt > 14) {
+ // Give up if we see too many zeros without
+ // a one, too.
+ Uart.state = STATE_ERROR_WAIT;
+ }
+ break;
+
+ case STATE_AWAITING_START_BIT:
+ Uart.posCnt++;
+ if(bit) {
+ if(Uart.posCnt > 25) {
+ // stayed high for too long between
+ // characters, error
+ Uart.state = STATE_ERROR_WAIT;
+ }
+ } else {
+ // falling edge, this starts the data byte
+ Uart.posCnt = 0;
+ Uart.bitCnt = 0;
+ Uart.shiftReg = 0;
+ Uart.state = STATE_RECEIVING_DATA;
+ LED_A_ON(); // Indicate we're receiving
+ }
+ break;
+
+ case STATE_RECEIVING_DATA:
+ Uart.posCnt++;
+ if(Uart.posCnt == 2) {
+ // time to sample a bit
+ Uart.shiftReg >>= 1;
+ if(bit) {
+ Uart.shiftReg |= 0x200;
+ }
+ Uart.bitCnt++;
+ }
+ if(Uart.posCnt >= 4) {
+ Uart.posCnt = 0;
+ }
+ if(Uart.bitCnt == 10) {
+ if((Uart.shiftReg & 0x200) && !(Uart.shiftReg & 0x001))
+ {
+ // this is a data byte, with correct
+ // start and stop bits
+ Uart.output[Uart.byteCnt] = (Uart.shiftReg >> 1) & 0xff;
+ Uart.byteCnt++;
+
+ if(Uart.byteCnt >= Uart.byteCntMax) {
+ // Buffer overflowed, give up
+ Uart.posCnt = 0;
+ Uart.state = STATE_ERROR_WAIT;
+ } else {
+ // so get the next byte now
+ Uart.posCnt = 0;
+ Uart.state = STATE_AWAITING_START_BIT;
+ }
+ } else if(Uart.shiftReg == 0x000) {
+ // this is an EOF byte
+ LED_A_OFF(); // Finished receiving
+ return TRUE;
+ } else {
+ // this is an error
+ Uart.posCnt = 0;
+ Uart.state = STATE_ERROR_WAIT;
+ }
+ }
+ break;
+
+ case STATE_ERROR_WAIT:
+ // We're all screwed up, so wait a little while
+ // for whatever went wrong to finish, and then
+ // start over.
+ Uart.posCnt++;
+ if(Uart.posCnt > 10) {
+ Uart.state = STATE_UNSYNCD;
+ }
+ break;
+
+ default:
+ Uart.state = STATE_UNSYNCD;
+ break;
+ }
+
+ // This row make the error blew circular buffer in hf 14b snoop
+ //if (Uart.state == STATE_ERROR_WAIT) LED_A_OFF(); // Error
+
+ return FALSE;