iodefsf.src

        .page  'i/odef.sf'       
;*****************************
;*      i/o definitions      *
;*****************************
;
unlsn    =$3f   ;  ieee unlisten command
untlk    =$5f   ;  ieee untalk command
notrdy   =$0    ;  not ready
talker   =$80   ;  ieee talker flag
lisner   =1     ;  ieee listener flag
eoiout   =$80   ;  talk with eoi
eoisnd   =$08   ;  not(eoi) to send
eoi      =$08   ;  not(eoi) to send
rdytlk   =$88   ;  talk no eoi
rdylst   =$1    ;  ready to listen
rndrdy   =rdytlk+rdylst         ;  random chnrdy
rndeoi   =eoiout+rdylst         ;  random w/ eoi
        
;i/o registers

; mos 6522-a

        *  =$1800        
;ieee control port
pb       *=*+1          ;  serial port
pa1      *=*+1          ; unused port
ddrb1    *=*+1          ;  serial data dir
ddra1    *=*+1          ; unused ddra
t1lc1    *=*+1          ;  timer 1 low counter
t1hc1    *=*+1          ;  timer 1 hi counter
t1ll1    *=*+1          ;  timer 1 low latch
t1hl1    *=*+1          ;  timer 1 hi latch
t2lc1    *=*+1          ;  timer 2 low counter
t2hc1    *=*+1          ;  timer 2 hi counter
sr1      *=*+1          ;  shift reg
acr1     *=*+1          ;  aux control reg
pcr1     *=*+1          ; 
ifr1     *=*+1          ; 
ier1     *=*+1          ; 
pota1    *=*+1          ; d0=photo sensor ,d1-d7=unused
;
;
;
;  bits for serial handshake
;
datin    =$1    ; data in line
datout   =$2    ;  data out
clkin    =$4    ; clock in
clkout   =$8    ; clock out
atna     =$10   ; atna ack
atn      =$80   ;  atn in
;
;
led0     =8     ;  act led
led1     =0     ;  no led
ledprt=$1c00    ;  on  pb  of  $1c00        
ledout=$1c02    ;  ddrb  of  $1c00  for  output-led         
;
;
;.end