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view level1/modules/dwread.asm @ 2886:fea5c20fdbfe
Various whitespace fixups
just to make less merge conflicts
| author | Tormod Volden <debian.tormod@gmail.com> |
|---|---|
| date | Sun, 24 Nov 2013 17:00:47 +0100 |
| parents | 0a3f4d8ea6d5 |
| children | 28ed72477814 |
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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 ARDUINO * Note: this is an optimistic routine. It presumes that the server will always be there, and * has NO timeout fallback. It is also very short and quick. DWRead clra ; clear Carry (no framing error) pshs u,x,cc ; preserve registers leau ,x ldx #$0000 loop@ tst $FF51 ; check for CA1 bit (1=Arduino has byte ready) bpl loop@ ; loop if not set ldb $FF50 ; clear CA1 bit in status register stb ,u+ ; save off acquired byte abx ; update checksum leay ,-y bne loop@ leay ,x ; return checksum in Y puls cc,x,u,pc ; restore registers and return ELSE IFNE JMCPBCK * NOTE: There is no timeout currently on here... DWRead clra ; clear Carry (no framing error) deca ; clear Z flag, A = timeout msb ($ff) tfr cc,b pshs u,x,dp,b,a ; preserve registers, push timeout msb leau ,x ldx #$0000 orcc #IntMasks loop@ ldb $FF4C bitb #$02 beq loop@ ldb $FF44 stb ,u+ abx leay ,-y bne loop@ tfr x,y ldb #0 lda #3 leas 1,s ; remove timeout msb from stack inca ; A = status to be returned in C and Z ora ,s ; place status information into the.. sta ,s ; ..C and Z bits of the preserved CC leay ,x ; return checksum in Y puls cc,dp,x,u,pc ; restore registers and return ELSE IFNE BECKER * NOTE: There is no timeout currently on here... DWRead clra ; clear Carry (no framing error) deca ; clear Z flag, A = timeout msb ($ff) tfr cc,b pshs u,x,dp,b,a ; preserve registers, push timeout msb leau ,x ldx #$0000 orcc #IntMasks loop@ ldb $FF41 bitb #$02 beq loop@ ldb $FF42 stb ,u+ abx leay ,-y bne loop@ tfr x,y ldb #0 lda #3 leas 1,s ; remove timeout msb from stack inca ; A = status to be returned in C and Z ora ,s ; place status information into the.. sta ,s ; ..C and Z bits of the preserved CC leay ,x ; return checksum in Y puls cc,dp,x,u,pc ; restore registers and return ENDC ENDC ENDC IFEQ BECKER+JMCPBCK+ARDUINO IFNE BAUD38400 ******************************************************* * 38400 bps using 6809 code and timimg ******************************************************* DWRead clra ; clear Carry (no framing error) deca ; clear Z flag, A = timeout msb ($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 ******************************************************* * 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 $00 ELSE ******************************************************* * 57600 (115200) bps using 6809 code and timimg ******************************************************* DWRead clra ; clear Carry (no framing error) deca ; clear Z flag, A = timeout msb ($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 ENDC ENDC ENDC