pokecrystal-board/home/handshake.asm
2018-06-24 16:13:22 +02:00

43 lines
546 B
NASM

PrinterReceive::
homecall _PrinterReceive
ret
AskSerial::
; send out a handshake while serial int is off
ld a, [wPrinterConnectionOpen]
bit 0, a
ret z
; if we're still interpreting data, don't try to receive
ld a, [wPrinterOpcode]
and a
ret nz
; once every 6 frames
ld hl, wHandshakeFrameDelay
inc [hl]
ld a, [hl]
cp 6
ret c
xor a
ld [hl], a
ld a, 12
ld [wPrinterOpcode], a
; handshake
ld a, $88
ld [rSB], a
; switch to internal clock
ld a, %00000001
ld [rSC], a
; start transfer
ld a, %10000001
ld [rSC], a
ret