Mercurial > hg > Members > kono > nitros9-code
view level1/modules/dwread.asm @ 2711:a1e65a5ef4cf lwtools-port
Moved Atari SIO read/write routines into main dwread.asm and dwwrite.asm
| author | Boisy Pitre <boisy.pitre@nuance.com> |
|---|---|
| date | Tue, 24 Jul 2012 10:09:58 -0500 |
| parents | 963688cd0596 |
| children | 8399491c0821 |
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******************************************************* * * DWRead * Receive a response from the DriveWire server. * Times out if serial port goes idle for more than 1.4 (0.7) seconds. * Serial data format: 1-8-N-1 * 4/12/2009 by Darren Atkinson * * Entry: * X = starting address where data is to be stored * Y = number of bytes expected * * Exit: * CC = carry set on framing error, Z set if all bytes received * X = starting address of data received * Y = checksum * U is preserved. All accumulators are clobbered * IFNE atari * ATARI SIO Version DWRead clrb clear carry pshs cc,a,x,y,u tfr x,u ldx #$0000 orcc #$50 * lda D.IRQENSHDW * sta IRQEN * ora #%00100000 * enable the serial input interrupt ldb SERIN read what is in the buffer lda #$13 sta SKCTL sta SKRES inloop@ lda D.IRQENSHDW ora #%00100000 sta IRQEN ldd #$0000 loop@ subd #$0001 beq outtahere@ pshs b ldb IRQST bitb #%00100000 puls b bne loop@ ldb SERIN lda D.IRQENSHDW sta IRQEN * check for framing error lda SKSTAT bpl outtahere@ framing error lsla bpl outtahere@ data input overrun stb ,u+ abx leay -1,y bne inloop@ stx 4,s bye sta SKRES clear framing or data input overrun bits puls cc,a,x,y,u,pc outtahere@ sta SKRES clear framing or data input overrun bits puls cc,a stx 2,s orcc #$01 puls x,y,u,pc ELSE IFNE BECKER * NOTE: There is no timeout currently on here... DWRead pshs cc,d,x,u leau ,x ldx #$0000 orcc #IntMasks loop@ ldb $FF41 bitb #$02 beq loop@ ldb $FF42 stb ,u+ abx leay -1,y bne loop@ tfr x,y puls cc andcc #^Carry orcc #Zero puls d,x,u,pc ELSE IFNE BAUD38400 ******************************************************* * 38400 bps using 6809 code and timimg ******************************************************* DWRead clra ; clear Carry (no framing error) deca ; clear Z flag, A = timeout msb ($ff) tfr cc,b pshs u,x,dp,b,a ; preserve registers, push timeout msb orcc #$50 ; mask interrupts tfr a,dp ; set direct page to $FFxx setdp $ff leau ,x ; U = storage ptr ldx #0 ; initialize checksum adda #2 ; A = $01 (serial in mask), set Carry * Wait for a start bit or timeout rx0010 bcc rxExit ; exit if timeout expired ldb #$ff ; init timeout lsb rx0020 bita <BBIN ; check for start bit beq rxByte ; branch if start bit detected subb #1 ; decrement timeout lsb bita <BBIN beq rxByte bcc rx0020 ; loop until timeout lsb rolls under bita <BBIN beq rxByte addb ,s ; B = timeout msb - 1 bita <BBIN beq rxByte stb ,s ; store decremented timeout msb bita <BBIN bne rx0010 ; loop if still no start bit * Read a byte rxByte leay ,-y ; decrement request count ldd #$ff80 ; A = timeout msb, B = shift counter sta ,s ; reset timeout msb for next byte rx0030 exg a,a nop lda <BBIN ; read data bit lsra ; shift into carry rorb ; rotate into byte accumulator lda #$01 ; prep stop bit mask bcc rx0030 ; loop until all 8 bits read stb ,u+ ; store received byte to memory abx ; update checksum ldb #$ff ; set timeout lsb for next byte anda <BBIN ; read stop bit beq rxExit ; exit if framing error leay ,y ; test request count bne rx0020 ; loop if another byte wanted lda #$03 ; setup to return SUCCESS * Clean up, set status and return rxExit leas 1,s ; remove timeout msb from stack inca ; A = status to be returned in C and Z ora ,s ; place status information into the.. sta ,s ; ..C and Z bits of the preserved CC leay ,x ; return checksum in Y puls cc,dp,x,u,pc ; restore registers and return setdp $00 ELSE IFNE H6309-1 ******************************************************* * 57600 (115200) bps using 6809 code and timimg ******************************************************* DWRead clra ; clear Carry (no framing error) deca ; clear Z flag, A = timeout msb ($ff) tfr cc,b pshs u,x,dp,b,a ; preserve registers, push timeout msb orcc #$50 ; mask interrupts tfr a,dp ; set direct page to $FFxx setdp $ff leau ,x ; U = storage ptr ldx #0 ; initialize checksum lda #$01 ; A = serial in mask bra rx0030 ; go wait for start bit * Read a byte rxByte leau 1,u ; bump storage ptr leay ,-y ; decrement request count lda <BBIN ; read bit 0 lsra ; move bit 0 into Carry ldd #$ff20 ; A = timeout msb, B = shift counter sta ,s ; reset timeout msb for next byte rorb ; rotate bit 0 into byte accumulator rx0010 lda <BBIN ; read bit (d1, d3, d5) lsra rorb bita 1,s ; 5 cycle delay bcs rx0020 ; exit loop after reading bit 5 lda <BBIN ; read bit (d2, d4) lsra rorb leau ,u bra rx0010 rx0020 lda <BBIN ; read bit 6 lsra rorb leay ,y ; test request count beq rx0050 ; branch if final byte of request lda <BBIN ; read bit 7 lsra rorb ; byte is now complete stb -1,u ; store received byte to memory abx ; update checksum lda <BBIN ; read stop bit anda #$01 ; mask out other bits beq rxExit ; exit if framing error * Wait for a start bit or timeout rx0030 bita <BBIN ; check for start bit beq rxByte ; branch if start bit detected bita <BBIN ; again beq rxByte ldb #$ff ; init timeout lsb rx0040 bita <BBIN beq rxByte subb #1 ; decrement timeout lsb bita <BBIN beq rxByte bcc rx0040 ; loop until timeout lsb rolls under bita <BBIN beq rxByte addb ,s ; B = timeout msb - 1 bita <BBIN beq rxByte stb ,s ; store decremented timeout msb bita <BBIN beq rxByte bcs rx0030 ; loop if timeout hasn't expired bra rxExit ; exit due to timeout rx0050 lda <BBIN ; read bit 7 of final byte lsra rorb ; byte is now complete stb -1,u ; store received byte to memory abx ; calculate final checksum lda <BBIN ; read stop bit anda #$01 ; mask out other bits ora #$02 ; return SUCCESS if no framing error * Clean up, set status and return rxExit leas 1,s ; remove timeout msb from stack inca ; A = status to be returned in C and Z ora ,s ; place status information into the.. sta ,s ; ..C and Z bits of the preserved CC leay ,x ; return checksum in Y puls cc,dp,x,u,pc ; restore registers and return setdp $00 ELSE ******************************************************* * 57600 (115200) bps using 6309 native mode ******************************************************* DWRead clrb ; clear Carry (no framing error) decb ; clear Z flag, B = $FF pshs u,x,dp,cc ; preserve registers orcc #$50 ; mask interrupts * ldmd #1 ; requires 6309 native mode tfr b,dp ; set direct page to $FFxx setdp $ff leay -1,y ; adjust request count leau ,x ; U = storage ptr tfr 0,x ; initialize checksum lda #$01 ; A = serial in mask bra rx0030 ; go wait for start bit * Read a byte rxByte sexw ; 4 cycle delay ldw #$006a ; shift counter and timing flags clra ; clear carry so next will branch rx0010 bcc rx0020 ; branch if even bit number (15 cycles) nop ; extra (16th) cycle rx0020 lda <BBIN ; read bit lsra ; move bit into carry rorb ; rotate bit into byte accumulator lda #0 ; prep A for 8th data bit lsrw ; bump shift count, timing bit to carry bne rx0010 ; loop until 7th data bit has been read incw ; W = 1 for subtraction from Y inca ; A = 1 for reading bit 7 anda <BBIN ; read bit 7 lsra ; move bit 7 into carry, A = 0 rorb ; byte is now complete stb ,u+ ; store received byte to memory abx ; update checksum subr w,y ; decrement request count inca ; A = 1 for reading stop bit anda <BBIN ; read stop bit bls rxExit ; exit if completed or framing error * Wait for a start bit or timeout rx0030 clrw ; initialize timeout counter rx0040 bita <BBIN ; check for start bit beq rxByte ; branch if start bit detected addw #1 ; bump timeout counter bita <BBIN beq rxByte bcc rx0040 ; loop until timeout rolls over lda #$03 ; setup to return TIMEOUT status * Clean up, set status and return rxExit beq rx0050 ; branch if framing error eora #$02 ; toggle SUCCESS flag rx0050 inca ; A = status to be returned in C and Z ora ,s ; place status information into the.. sta ,s ; ..C and Z bits of the preserved CC leay ,x ; return checksum in Y puls cc,dp,x,u,pc ; restore registers and return setdp $00 ENDC ENDC ENDC ENDC