[Coco] Speech Systems Stereo Pak
go4retro at go4retro.com
Sat Oct 17 22:55:15 EDT 2020
On 10/17/2020 8:50 PM, Bill Pierce via Coco wrote:
> Tim, I looked through my notes and what I have on the SS Stereo Pak was what I found in Lester's sources for Lyra's "TV Play" and Musica's SSPak options. Basically the code was the same in each one.
> There is a "setup" routine to set the unit to "ready for data", that is done once, before interrupts are blocked and sound loop starts
> * Set up Speech Systems Stereo Paksspkon clr >$FF71 clr >$FF73 lda #$FF sta >$FF70 sta >$FF72 lda #$04 sta >$FF71 sta >$FF73
This makes sense if the Stereo Pak uses a MC6821 as the means to store
and output the 8 bit values.
BASE = $ff70
PORTA = BASE
DDRA = BASE
CTRLA = BASE +1
PORTB = BASE + 2
DDRB = BASE + 2
CTRLB = BASE + 3
DDR_ACCESS = $04 ; 0 = DDR, 1 = PORT
clr CTRLA ; select DDR in PORT/DDR select
clr CTRLB ; select DDR in PORT/DDR select
*To be safe, I'd probably zero out the PORTS as well:*
; now, start sending data...
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