On Mon, 7 Sep 1998, Chris Cracknell wrote:
> I think I might have my clock finished. The sprites are all doing what I
> want them to and I just implimented a requested feature. A friend liked the
> clock but didn't like the 24 hour format. So I made the B/W switch toggle
> between a 12 hour and 24 hour clock. I got it working but I had a hard time
> doing it. There seems to be a discepancy between what the Stella manual says
> and what my 2600 says.
I can't get the 24hr clock to work on stella. But the sprites kick ass!!!
Very cool...
> In the Stella Manual the data bits for SWCHB says:
>
> D3 - B/W Switch
I don't remember the others, but the bw/color switch is indeed d3.
> But here is the code I had to use to read the B/W switch
>
> joy lda SWCHB
> and %0010000
> cmp %0010000
> bne swa
> lda HOURS
> cmp #$0c
> bpl swa
> lda #$17
> sta HOURS
>
> On my 2600 D5 is the B/W switch, D3 is select, and D2 is reset.
>
> Is there an error in the manual, my code, or is there something odd with
> my 2600.
Try this to read the bw/color switch:
joy lda SWCHB
and #08 ; sets the z flag if bit 3 = 0
; clears it otherwise
beq bw ; I forget which is black and white, 0 or 1... :)
color ...
...
...
This worked in my hacked version of the playfield demo
(on PCAE and multiple 2600s). And it matches what the
Stella docs say.
-Chris
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