Mercurial > hg > Members > kono > nitros9-code
view level1/modules/dwread.asm @ 2182:b1b374ada668
Added 38.4kbps routines from Darren Atkinson
| author | boisy |
|---|---|
| date | Sun, 08 Mar 2009 14:11:52 +0000 |
| parents | 660cc987e18d |
| children | 27f07aa0bca0 |
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IFNE BAUD38400 ****************************************************************************** * COCO 38400 BAUD BIT-BANGER RECEIVER ****************************************************************************** * * WAITS FOR A SPECIFIED TIMEOUT PERIOD UNTIL A START-BIT APPEARS ON THE * BIT-BANGER INPUT. DATA RECEPTION IS INITIATED IF A START-BIT APPEARS * BEFORE THE TIMEOUT PERIOD EXPIRES. THE SERIAL DATA FORMAT MUST BE: * 1 START BIT, 8 DATA BITS, NO PARITY, 1..2 STOP BITS. * * DATA RECPEPTION TERMINATES WHEN: * - A PERIOD OF 4 MS ELLAPSES WITHOUT A NEW START BIT * - A FRAMING ERROR IS DETECTED. * * ON ENTRY: * X = ADDRESS FOR DATA STORAGE * A = TIMEOUT VALUE (125 = APPROX ONE SECOND) * * ON EXIT: * Y = DATA CHECKSUM * D = NUMBER OF BYTES RECEIVED * X AND U ARE PRESERVED * CC.CARRY IS SET ONLY IF A FRAMING ERROR WAS DETECTED * ****************************************************************************** BBIN EQU $FF22 ; BIT-BANGER INPUT ADDRESS BUFBAS EQU 1 ; OFFSET TO STORAGE ADDRESS ON STACK DWRead RCV38K CLRB ; CLEAR CARRY FLAG (NO FRAMING ERROR) PSHS U,X,CC ; PRESERVE REGISTERS ORCC #$50 ; MASK INTERRUPTS TFR D,Y ; SET Y TO INITIAL TIMEOUT COUNTER LEAU ,X ; POINT U TO STORAGE BUFFER LDX #0 ; INITIALIZE CHECKSUM LDA #1 ; A = SERIAL INPUT MASK WAIT1 LEAY ,Y ; TEST TIMEOUT COUNTER BEQ FINISH ; BRANCH IF TIMEOUT HAS EXPIRED WAIT2 BITA BBIN ; CHECK FOR START BIT BEQ BSTART ; BRANCH IF START BIT DETECTED LEAY -1,Y ; DECREMENT TIMEOUT COUNTER BITA BBIN ; CHECK FOR START BIT BNE WAIT1 ; LOOP IF STILL NO START BIT BSTART LDY #BBIN ; POINT Y TO BIT BANGER INPUT REGISTER LEAU ,U ; 4 CYCLE DELAY LDB #$7F ; INITIALIZE B FOR SHIFT COUNTER RDLOOP TST ,Y++ ; 9 CYCLE DELAY LDA ,--Y ; READ DATA BIT LSRA ; SHIFT DATA INTO CARRY RORB ; ROTATE INTO BYTE ACCUMULATOR BCS RDLOOP ; LOOP UNTIL 8 DATA BITS HAVE BEEN READ STB ,U+ ; STORE RECEIVED BYTE ABX ; ACCUMULATE CHECKSUM CLRA ; DO THE EQUIVALENT OF.. INCA ; ..LDA #1 USING 4 CYCLES ANDA ,Y ; CHECK FOR THE STOP BIT LDY #128 ; SET TIMEOUT COUNTER TO 4MS TSTA ; IF STOP BIT IS GOOD THEN.. BNE WAIT2 ; ..GO WAIT FOR NEXT BYTE FINISH INCA ; A=1 IF FRAMING ERROR, 2 OTHERWISE ORA ,S ; SETS CARRY BIT IN CC VALUE ON.. STA ,S ; ..STACK IF FRAMING ERROR DETECTED LEAY ,X ; RETURN CHECKSUM IN Y TFR U,D ; CALCULATE NUMBER.. SUBD BUFBAS,S ; ..OF BYTES RECEIVED PULS CC,X,U,PC ; RESTORE REGISTERS AND RETURN ELSE IFNE H6309-1 ** ** Rev 3 Notes: ** ** For CoCo 1,2 or 3 ** 6809 Timing ** No Read Count in Receiver ** ****************************************************************************** * COCO 57600 / 115.2K BAUD BIT-BANGER RECEIVER ****************************************************************************** * * WAITS FOR A SPECIFIED TIMEOUT PERIOD UNTIL A START-BIT APPEARS ON THE * BIT-BANGER INPUT. DATA RECEPTION IS INITIATED IF A START-BIT APPEARS * BEFORE THE TIMEOUT PERIOD EXPIRES. THE SERIAL DATA FORMAT MUST BE: * 1 START BIT, 8 DATA BITS, NO PARITY, 1..2 STOP BITS. * * DATA RECPEPTION TERMINATES WHEN: * - A PERIOD OF APPROX 5.5 MS (2.75 MS) ELLAPSES WITHOUT A NEW START-BIT * - A FRAMING ERROR IS DETECTED. * * ON ENTRY: * X = START ADDRESS FOR DATA STORAGE * A = TIMEOUT VALUE (182 = APPROX ONE SECOND @ 0.89 MHZ) * * ON EXIT: * Y = DATA CHECKSUM * D = ACTUAL NUMBER OF BYTES RECEIVED * X AND U ARE PRESERVED * CC.CARRY IS SET ONLY IF A FRAMING ERROR WAS DETECTED * ****************************************************************************** BBIN EQU $FF22 ; BIT-BANGER INPUT ADDRESS BCTR EQU 1 ; OFFSET TO BIT LOOP COUNTER ON STACK RCVSTA EQU 2 ; OFFSET TO CC VALUE ON THE STACK BUFBAS EQU 4 ; OFFSET TO STORAGE ADDRESS ON STACK DWRead RCV56K CLRB ; CLEAR CARRY FLAG (NO FRAMING ERROR) PSHS U,X,DP,CC ; PRESERVE REGISTERS STA ,--S ; STORE INITIAL TIMEOUT DURATION LDD #$01FF ; A = SERIAL INPUT MASK, B = $FF ORCC #$50 ; MASK INTERRUPTS TFR B,DP ; SET DIRECT PAGE TO $FFXX SETDP $FF ; INFORM ASSEMBLER OF NEW DP VALUE LEAU ,X ; POINT U TO STORAGE ADDRESS LDX #0 ; INITIALIZE CHECKSUM BRA WAIT1 ; GO WAIT FOR A START BIT BSTART LEAU 1,U 5 \ 11 ; ADVANCE THE STORAGE PTR CLR ,S 6 / ; RESET TIMEOUT MSB TO 1 LDB <BBIN 4 \ ; BIT 0 LSRB 2 | RORB 2 | 15 LDA #3 2 | STA BCTR,S 5 / BLOOP LDA <BBIN 4 \ ; BITS 1,3 AND 5 LSRA 2 | 15 RORB 2 | DEC BCTR,S 7 / LDA <BBIN 4 \ ; BITS 2,4 AND 6 LSRA 2 | RORB 2 | 16 LDA BCTR,S 5 | BNE BLOOP 3 / LDA <BBIN 4 \ ; BIT 7 LSRA 2 | RORB 2 | 16 ABX 3 | ; ACCUMULATE CHECKSUM STB -1,U 5 / ; PUT BYTE INTO STORAGE LDA <BBIN 4 \ ; STOP BIT ANDA #1 2 | 9 ; MASK OUT ALL OTHER BITS (1-7) BEQ FINISH 3 / ; BRANCH IF FRAMING ERROR WAIT1 BITA <BBIN 4 \ 7 ; TWO RAPID TESTS FOR NEXT START BIT BEQ BSTART 3 / BITA <BBIN 4 \ BEQ BSTART 3 | 9 LDB #$FF 2 / ; INIT TIMEOUT LSB WAIT2 BITA <BBIN 4 \ BEQ BSTART 3 | 9 SUBB #1 2 / ; DECREMENT TIMEOUT LSB BITA <BBIN 4 \ BEQ BSTART 3 | 10 BCC WAIT2 3 / ; LOOP UNTIL TIMEOUT LSB < 0 BITA <BBIN 4 \ BEQ BSTART 3 | 11 LDB ,S 4 / ; GET TIMEOUT MSB BITA <BBIN 4 \ BEQ BSTART 3 | 9 SUBB #1 2 / ; DECREMENT TIMEOUT MSB BITA <BBIN 4 \ BEQ BSTART 3 | 11 STB ,S 4 / ; STORE TIMEOUT MSB BITA <BBIN 4 \ BEQ BSTART 3 | 10 BCC WAIT1 3 / ; LOOP IF TIMEOUT NOT EXPIRED FINISH INCA ; IF FRAMING ERROR THEN A=1 ELSE A=2 ORA RCVSTA,S ; SET CARRY BIT IN CC VALUE ON.. STA RCVSTA,S ; ..THE STACK ONLY IF FRAMING ERROR LEAY ,X ; RETURN CHECKSUM IN Y TFR U,D ; CALCULATE ACTUAL NUMBER.. SUBD BUFBAS,S ; ..OF BYTES RECEIVED LEAS 2,S ; POP TIMEOUT AND BIT LOOP COUNTERS PULS CC,DP,X,U,PC ; RESTORE REGISTERS AND RETURN SETDP $00 ELSE ** Rev 4 Notes: ** ** For CoCo 2 or 3 ** 6309 Native Mode ** No Read Count in Receiver ** ****************************************************************************** * COCO 57600 / 115.2K BAUD BIT-BANGER RECEIVER ****************************************************************************** * * WAITS FOR A SPECIFIED TIMEOUT PERIOD UNTIL A START-BIT APPEARS ON THE * BIT-BANGER INPUT. DATA RECEPTION IS INITIATED IF A START-BIT APPEARS * BEFORE THE TIMEOUT PERIOD EXPIRES. THE SERIAL DATA FORMAT MUST BE: * 1 START BIT, 8 DATA BITS, NO PARITY, 1..2 STOP BITS. * * DATA RECPEPTION TERMINATES WHEN: * - A PERIOD OF APPROX 5.5 MS (2.75 MS) ELLAPSES WITHOUT A NEW START-BIT * - A FRAMING ERROR IS DETECTED. * * ON ENTRY: * X = START ADDRESS FOR DATA STORAGE * A = TIMEOUT VALUE (183 = APPROX ONE SECOND @ 0.89 MHZ) * * ON EXIT: * Y = DATA CHECKSUM * D = ACTUAL NUMBER OF BYTES RECEIVED * X AND U ARE PRESERVED * E AND F ARE CLOBBERED * CC.CARRY IS SET ONLY IF A FRAMING ERROR WAS DETECTED * ****************************************************************************** BBIN EQU $FF22 ; BIT-BANGER INPUT ADDRESS RCVSTA EQU 0 ; OFFSET TO CC VALUE ON THE STACK BUFBAS EQU 1 ; OFFSET TO STORAGE ADDRESS ON STACK DWRead RCV56K CLRB ; CLEAR CARRY FLAG (NO FRAMING ERROR) PSHS U,X,CC ; PRESERVE REGISTERS LDU #BBIN ; POINT U TO BIT BANGER INPUT TFR A,F ; COPY INTITAL TIMEOUT TO F LDD #$01FF ; A = SERIAL IN MASK, B = TIMEOUT LSB LEAY ,X ; POINT Y TO STORAGE ADDRESS LDX #0 ; INITIALIZE CHECKSUM ORCC #$50 ; MASK INTERRUPTS * LDMD #1 ; REQUIRES 6309 NATIVE MODE BRA WAIT1 ; GO WAIT FOR A START BIT BSTART SEXW 4 \ ; 4-CYCLE DELAY (CLOBBERS D) LDW #$005A 4 | 11 ; PREP SHIFT COUNTER / TIMING FLAGS BRA BSAMP 3 / ; ENTER THE LOOP BLOOP BCC BSAMP 3 ; BRANCH IF A 15-CYCLE BIT NOP 1 ; ONE MORE FOR A 16-CYCLE BIT BSAMP LDA ,U 4 \ ; SAMPLE DATA BIT LSRA 1 | ; SHIFT INTO CARRY RORB 1 | 12 ; ROTATE INTO BYTE ACCUMULATOR NOP 1 | ; DELAY CYCLE LSRW 2 | ; BUMP THE SHIFT COUNTER / TIMING FLAGS BNE BLOOP 3 / ; LOOP UNTIL BIT 6 HAS BEEN SAMPLED LEAU ,U 4 ; CONSUME 4 CYCLES (16 TOTAL FOR BIT 6) LDA ,U 4 \ ; BIT 7 LSRA 1 | RORB 1 | 15 STB ,Y+ 5 | ; PUT BYTE INTO STORAGE ABX 1 | ; ACCUMULATE CHECKSUM LDD #$01FF 3 / ; A = SERIAL IN MASK, B = TIMEOUT LSB ANDA ,U 4 \ 7 ; STOP BIT BEQ FINISH 3 / ; BRANCH IF FRAMING ERROR WAIT1 BITA ,U 4 \ 7 ; TWO RAPID TESTS FOR NEXT START BIT BEQ BSTART 3 / WAIT2 BITA ,U 4 \ BEQ BSTART 3 | 9 SUBB #1 2 / ; DECREMENT TIMEOUT LSB BITA ,U 4 \ BEQ BSTART 3 | 10 BCC WAIT2 3 / ; LOOP UNTIL TIMEOUT LSB < 0 BITA ,U 4 \ 7 BEQ BSTART 3 / BITA ,U 4 \ BEQ BSTART 3 | 10 SUBF #1 3 / ; DECREMENT TIMEOUT MSB BITA ,U 4 \ BEQ BSTART 3 | 10 BCC WAIT1 3 / ; LOOP IF TIMEOUT NOT EXPIRED FINISH INCA ; IF FRAMING ERROR THEN A=1 ELSE A=2 ORA RCVSTA,S ; SET CARRY BIT IN CC VALUE ON.. STA RCVSTA,S ; ..THE STACK ONLY IF FRAMING ERROR TFR Y,D ; CALCULATE ACTUAL NUMBER.. SUBD BUFBAS,S ; ..OF BYTES RECEIVED LEAY ,X ; RETURN CHECKSUM IN Y PULS CC,X,U,PC ; RESTORE REGISTERS AND RETURN ENDC ENDC