[Coco] CoCo 3 keyboard interrupt

[Robert Gault]

Tim,

This may not be the best example of the technique but I tested it on a real Coco3 and the border 
color changes with a key press.

* Test of keyboard IRQ

	ORG	$7000
START	ORCC	#$50
	LDA	#2	SETUP KEY IRQ
	STA	$FF92
	CLR	$FF02	MAY NOT BE NEEDED
	LDX	#IRQV	INSTALL OUR K-IRQ ROUTINE
	STX	$FEF8
	LDA	#$7E	JMP
	STA	$FEF7
	CLR	COLOR	DATA BYTE
	ANDCC	#$AF
	RTS

IRQV	LDA	$FF92	TEST FOR A KEY IRQ
	BITA	#2
	LBEQ	$10C	IF NOT KEY DO NORMAL IRQ
	INC	COLOR	IT WAS A KEY STROKE
	LDA	COLOR
	STA	$FF9A	CHANGE BORDER COLOR
	RTI		RETURN FROM IRQ

COLOR	FCB	0
	END	START


tim lindner wrote:
> Does any one have code prepared to test the keyboard interrupt? Or
> know of a program that uses it?
>
> I’ve heard reports it is broken in MAME. I’d like to fix it.
>