Mercurial > hg > Members > kono > nitros9-code
changeset 2546:f0977fc3f2d6
Added code for Gary's CoCo3FPGA interface
| author | boisy |
|---|---|
| date | Sat, 12 Jun 2010 11:59:39 +0000 |
| parents | cb2bec98a11d |
| children | 141cfa8a4302 |
| files | level1/modules/dwread.asm level1/modules/dwwrite.asm |
| diffstat | 2 files changed, 106 insertions(+), 4 deletions(-) [+] |
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--- a/level1/modules/dwread.asm Sun May 30 22:58:04 2010 +0000 +++ b/level1/modules/dwread.asm Sat Jun 12 11:59:39 2010 +0000 @@ -18,6 +18,51 @@ * + IFNE BECKER +DWRead clra ; clear Carry (no framing error) + deca ; clear Z flag, A = timeout msb ($ff) + tfr cc,b + pshs u,x,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 = $01 (serial in mask), set Carry + +* Wait for byte or timeout +rx0010 bcc rxExit ; exit if timeout expired + ldb #$ff ; init timeout lsb +rx0020 lda $FF41 ; check for byte ready + bita #$01 + bne rxByte ; branch if start bit detected + subb #1 ; decrement timeout lsb + bcc rx0020 ; loop until timeout lsb rolls under + beq rxByte + addb ,s ; B = timeout msb - 1 + stb ,s ; store decremented timeout msb + bra rx0010 ; loop if still no start bit + +* Read a byte +rxByte ldb $FF42 + + stb ,u+ ; store received byte to memory + abx ; update checksum + ldb #$ff ; set timeout lsb for next byte + 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,x,u,pc ; restore registers and return +; setdp $00 + + ELSE IFNE BAUD38400 ******************************************************* * 38400 bps using 6809 code and timimg @@ -240,5 +285,4 @@ ENDC ENDC - - + ENDC
--- a/level1/modules/dwwrite.asm Sun May 30 22:58:04 2010 +0000 +++ b/level1/modules/dwwrite.asm Sat Jun 12 11:59:39 2010 +0000 @@ -16,6 +16,65 @@ * + IFNE BECKER +DWWrite pshs u,d,cc ; preserve registers + orcc #$50 ; mask interrupts +; ldu #BBOUT ; point U to bit banger out register +; lda 3,u ; read PIA 1-B control register +; anda #$f7 ; clear sound enable bit +; sta 3,u ; disable sound output +; fcb $8c ; skip next instruction + +txByte + lda ,x+ + sta $FF42 + leay -1,y ; decrement byte counter + bne txByte ; loop if more to send + + puls cc,d,u,pc ; restore registers and return + + + ELSE + IFNE H6309-1 +******************************************************* +* 57600 (115200) bps using 6809 code and timimg +******************************************************* + +DWWrite pshs dp,d,cc ; preserve registers + orcc #$50 ; mask interrupts + ldd #$04ff ; A = loop counter, B = $ff + tfr b,dp ; set direct page to $FFxx + setdp $ff + ldb <$ff23 ; read PIA 1-B control register + andb #$f7 ; clear sound enable bit + stb <$ff23 ; disable sound output + fcb $8c ; skip next instruction + +txByte stb <BBOUT ; send stop bit + ldb ,x+ ; get a byte to transmit + nop + lslb ; left rotate the byte two positions.. + rolb ; ..placing a zero (start bit) in bit 1 +tx0020 stb <BBOUT ; send bit (start bit, d1, d3, d5) + rorb ; move next bit into position + exg a,a + nop + stb <BBOUT ; send bit (d0, d2, d4, d6) + rorb ; move next bit into position + leau ,u + deca ; decrement loop counter + bne tx0020 ; loop until 7th data bit has been sent + + stb <BBOUT ; send bit 7 + ldd #$0402 ; A = loop counter, B = MARK value + leay ,-y ; decrement byte counter + bne txByte ; loop if more to send + + stb <BBOUT ; leave bit banger output at MARK + puls cc,d,dp,pc ; restore registers and return + setdp $00 + + ELSE IFNE BAUD38400 ******************************************************* * 38400 bps using 6809 code and timimg @@ -130,5 +189,4 @@ ENDC ENDC - - + ENDC