; season - junior
;
; author: hackbard@hackdaworld.dyndns.org
;


; at90s2313
; setup:
; vcc card --- vcc cam
; rst card --- rst cam --- atmel t0 (pd4)
; clk card --- clk cam --- atmel t1 (pd5)
; gnd card --- gnd cam --- atmel gnd
; i/o card --- atmel int0 (pd2)
; i/o cam  --- atmel int1 (pd3)

.include "../include/2313def.inc"

; functions by now:
;
; stupid mode only by now. just see what cam/card do and redirect
; this to card/cam.
;
; next implementation:
; 
; try to read one byte of card/cam communication and output via uart.
; output time information in some way.
;
; future:
;
; buffer/parse whole strings and decide whether to send to card or not.

;
; interrupt vectors:
;

; reset
rjmp INIT

; int0
rjmp REC_CARD

; int1
rjmp REC_CAM

; timer/counter capt 1
reti

; timer/counter compare
reti

; timer/counter overflow 1
rjmp T1_OVERFLOW

; timer/counter overflow 0
reti

; uart rx complete
reti

; uart data register empty
reti

; uart tx complete
reti

; analog comparator
reti

;
; init routine
;

INIT:

; set stackpointer
ldi r16,low(RAMEND)
out SPL,r16

; enable interrupts int0,int1
ldi r16,((1<<INT0)|(1<<INT1))
out GIMSK,r16
; int0/1 setup
ldi r16,((1<<ISC01)|(1<<ISC00)|(1<<ISC10)|(1<<ISC11))
out MCUCR,r16
in r16,MCUCR
sbic PORTD,PD2
cbr r16,ISC00
out MCUCR,r16
sbic PORTD,PD3
cbr r16,ISC10
out MCUCR,r16

; enable t/c overflow interrupt
ldi r16,(1<<TOIE1)
out TIMSK,r16
; setup t/c
ldi r16,((1<<CS12)|(1<<CS11)|(1<<CS10))
out TCCR1B,r16

; init bitcounter and overflow counter
ldi r20,0 ; bitcounter
ldi r21,0 ; register for constructing the byte
ldi r22,0 ; overflow counter

; constant 1 in r1
ldi r16,1
mov r1,r16

; enable interrupts (global)
sei

;
; rec_card routines
;

REC_CARD:

; int0 -> input, int1 -> output
ldi r16,(1<<DDD3)
out DDRD,r16

; decide what to do
sbic PORTD,PD2
rjmp REC_CARD_HIGH
rjmp REC_CARD_LOW

REC_CARD_HIGH:

; output high on port to cam
ldi r16,(1<<PD3)
out PORTD,r16

; toggle int0 sense
in r16,MCUCR
cbr r16,ISC00
out MCUCR,r16

reti

REC_CARD_LOW:

; output low on port to cam
ldi r16,0
out PORTD,r16

; toggle int0 sense
in r16,MCUCR
cbr r16,ISC00
out MCUCR,r16

reti

;
; rec_cam routines
;

REC_CAM:

; int1 -> input, int0 -> output
ldi r16,(1<<DDD2)
out DDRD,r16

; decide what to do
sbic PORTD,PD3
rjmp REC_CAM_HIGH
rjmp REC_CAM_LOW

REC_CAM_HIGH:

; output high on port to card
ldi r16,(1<<PD2)
out PORTD,r16

; toggle int1 sense
in r16,MCUCR
cbr r16,ISC10
out MCUCR,r16

reti

REC_CAM_LOW:

; output low on port to card
ldi r16,0
out PORTD,r16

; toggle int 1 sense
in r16,MCUCR
cbr r16,ISC10
out MCUCR,r16

reti

;
; t1_overflow routine
;

T1_OVERFLOW:

add r22,r1 ; inc counter overflow register

reti