itty-bitty-vtty/scc.s

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ArmAsm
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2021-04-05 00:22:43 +00:00
lst off
exp off
*
* read slot 7 ssc card.
*
*
cmdb equ $c038
cmda equ $c039
datab equ $c03a
dataa equ $c03b
cout equ $fded
read mac
ldx #]1
if 3=]1
stx cmda
lda cmda
else
stx cmdb
lda cmdb
fin
sta buffer,x
<<<
lst on
org $0800
mx %11
db $01 ; prodos boot id
boot
* clc
* xce
* cli
sei
ldx #24
lda #$80+$0d
:cs jsr cout
dex
bpl :cs
SSC equ $c088+$70
init
* command register - DTR+, IRQ-, TX IRQ-, ECHO-, PARITY-
lda #%0000_1011
sta SSC+2
*control - 9600, BRG, /1
lda #%0_00_1_1110
sta SSC+3
* read 4 registers
loop
; status first
lda SSC+1
sta buffer+1
lda SSC+0
sta buffer+0
lda SSC+2
sta buffer+2
lda SSC+3
sta buffer+3
ldx #3
:cmp lda buffer,x
cmp prev,x
bne :delta
dex
bpl :cmp
bra wailoop
:delta
ldx #0
:print
lda buffer,x
phx
pha
lsr
lsr
lsr
lsr
tax
lda hex,x
jsr cout
pla
and #$0f
tax
lda hex,x
jsr cout
lda #" "
jsr cout
plx
inx
cpx #4
bcc :print
lda #$80+$0d
jsr cout
* store prev. values.
ldx #3
:copy lda buffer,x
sta prev,x
dex
bpl :copy
wailoop
* wai
brl loop
nop
nop
stp
hex asc "0123456789abcdef"
buffer ds 16
prev ds 16
lst off
* ds \
ds 1024+$0800-*
sav scc.bin