ChetSimpson / cyd-gmc

SN76489 music player based on CyD

CyD for Game Master Cartridge

Music player for CoCo and Dragon computers targetting the SN76489 in the Game Master Cartridge.

Work in progress. Plays two tone channels plus a noise channel with frequency controlled by the third tone channel for percussion.

Derived from CyD (Copyright 2013-2015 Ciaran Anscomb)

https://github.com/sixxie/cyd

Modified for the SN76489 by Stewart Orchard 2018

Quick Start

Needs: asm6809, bin2cas.pl, dzip, perl

git clone https://github.com/sorchard001/cyd-gmc
cd cyd-gmc
make
xroar -cart gmc -no-cart-autorun cyd_gmc.bin

Timing is derived from the video refresh rate, meaning the playback tempo will be different for PAL and NTSC machines. The demo tune is arranged for a PAL machine. Increase the note length in music.s from 6 to 7 to slow down the playback speed for NTSC:

; basic note length
n1	equ	6	; PAL
n1	equ	7	; NTSC

Further Info

Game Master Cartridge design by John Linville:

http://www.vintageisthenewold.com/game-master-cartridge-enables-better-games-for-coco/

SN76489 information:

http://www.smspower.org/Development/SN76489