>This one didn't work for me. I just got a lot of
>high-ascii characters.
The obvious answer is the out-of-spec signaling, but of course at this
speed, cabling becomes really important regardless if the signals are in
spec or not. I'm using about 2 feet of thick, stranded copper wires. Not
sure if cabling will help.
I don't think it's the timing. The timing is pretty good - at 10.329 cycles
per bit and 10 bits to send per character, you need 9 of these delays
between bits or 92.97 cycles, and I'm using 93. The delays between bits are
10,10,11,10,11,10,11,10,10 cycles, which I think is pretty ideal. Of
course, this assumes that the 2600 runs at *exactly* 1.19 Mhz... How
accurate is the 2600's clock?
I'd like to hear if anyone else gets it to work at 115200.
Regardless, if anyone has one of those fancy TTL converters, here's a
modified version of the 115200 bps program that should work with one:
processor 6502
include "vcs.h"
include "macro.h"
ORG $0080
noreset
lda SWCHB
lsr
iny
sty COLUBK
BCS noreset
keepgoing
; ldy #20
; jsr WSYNCY
shit
lda $f000,x
pha
lsr
lsr
lsr
lsr
jsr conv2hex
pla
jsr conv2hex
lda #32
jsr OUT232
inc $f9
lda $f9
and #$0f
sta $f9
bne noret
lda #13
jsr OUT232
noret
inc $fa
ldx $fa
bne keepgoing
inc shit+2
bne keepgoing
brk
conv2hex
and #$0f
cmp #10
bcc noadd
adc #6
noadd
adc #48
OUT232 LDX #0 ; output low for start bit
STX SWCHA
LDX #3 ; init count for 4 bit pairs
; EOR #$FF
sleep 4
OUT232b
STA SWCHA
ROR ; rotate out next bit
sleep 4
STA SWCHA
ROR ; rotate out next bit
DEX ; decrement counter
BPL OUT232b ; loop until 8 bits sent
STX SWCHA
RTS
echo ($f9-*)," bytes free"
.byte
0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0
.byte
0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0
start
sei
cld
ldx #$FF
txs
lda #0
clearmem
sta 0,x
dex
bne clearmem
ldx #$7F
loop2
lda $f000,x
sta $80,x
dex
bpl loop2
lda #1
sta SWACNT
lda #$00
sta SWCHA
rerestart
ldy #200
delay
WSYNCY STY WSYNC ; wait a line
DEY ; decrement line counter
BNE WSYNCY ; loop until done
ldx #0
jmp $0080
ORG $107C
.word start+$f80
.word start+$f80
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