This was an interesting board, a collaboration between Stuart Holmes (hardware) and Joe Savlini (software), both members of the Merseyside Nascom User Group. It was a big board – the same size as a Nascom-2 at 12″x8″. I think it was only ever sold as a kit. It was sold for less than £100 – which was cheap compared to most of the colour graphics cards, never mind one with so much extra on it.

It used the TMS9929 graphics processor with 16k of RAM. The TMS9929 is the PAL version of the TMS9918, which was used on the MSX computer design that was announced in June 1983.

Specifications
256×192 resolution on a TV screen
15 unique colours plus transparent
Outputs for RGB
Accessed via Z80 I/O ports so it took up no address space in the system
32 “layered” sprite planes, allowing 32 sprites in 8×8, 16×16 or 32×32 pixel sizes
Sprite collision sensing without having to read the screen memory
Sprites can pass over each other as they are on different layers

The board also included:

A Z80 CTC chip for timing operations, with three of its channels brought out to a plug
Two AY-3-8910 sound generator chips
An eight channel, eight bit ADC intended for use with joysticks or similar
2k of battery-backed static RAM accessed via I/O ports on the sound generator chips
Space for a real time clock

The board required I/O ports not decoded on the standard system so it was supplied with a replacement I/O PROM.

agc-a1

agc-a2

agc-a3

agc-a4

agc-a5

agc-a6

agc-a7


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