shithub: pokecrystal

ref: 01618d3cc46af567eea6c72ec88a2488002ca2b0
dir: /home/handshake.asm/

View raw version 
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
	ldh [rSB], a

; switch to internal clock
	ld a, (0 << rSC_ON) | (1 << rSC_CLOCK)
	ldh [rSC], a

; start transfer
	ld a, (1 << rSC_ON) | (1 << rSC_CLOCK)
	ldh [rSC], a

	ret