org $600

jmp recieve

; wait for high on pra bit 0, min 10us

wait_for_getit:
getit:
lda pra
and #$01
cmp #$01
bne getit
rts


; send high on pra bit 1

send_gotit:
lda #2
sta pra

waitforlow:
lda pra
and #$01
cmp #$00
bne waitforlow

lda #0
sta pra

rts

; set up DDRA, DDRB. PRB and PRB input, PRA bit 1 output
setin:
lda #$02
sta ddra
lda #$00
sta ddrb
rts


recieve:
; Set input mode
jsr setin

ldx #>texta
ldy #<texta
jsr string

; Skip Junk byte
jsr Wait_for_Getit
jsr Send_Gotit

; Get 4 Information Bytes
ldx #$00
loop:
jsr Wait_for_getit
lda prb
sta $90,x
jsr send_gotit
inx
cpx #$04
bne loop

;Display startup text
jsr clear
ldx #>textb
ldy #<textb
jsr string

;Display start address
lda $91
jsr hexout
lda $90
jsr hexout

; Display " -> "
ldx #>textc
ldy #<textc
jsr string

; display end address
lda $93
jsr hexout
lda $92
jsr hexout

; Wait for confirmation
ldx #>texte
ldy #<texte
jsr string

jsr kbwait

; Clear ready for receive
ldx #$00
ldy #$00

startin:
; Pull in byte
jsr wait_for_getit
lda prb
sta ($90),y

; Flick LED in confirmation
sta LED

; Increment address pointer
clc
lda $90
adc #$01
sta $90
lda $91
adc #$00
sta $91
jsr send_gotit

lda $90
cmp $92
bne startin

lda $91
cmp $93
bne startin

jsr clear
ldx #>textd
ldy #<textd
jsr string

jsr kbwait
brk

texta:
dc.b "Waiting for data",$0d,$0a,"from host...",0

textb:
dc.b "Get to address:",$0d,$0a,"Hex ",0

textc:
dc.b $20,"->",$20,0

textd:
dc.b "Received Data!",0

texte:
dc.b $0a,"Press any key",0