Sunday, September 23, 2007


After tracing the game code, I found that the sound chip is accessed via external ram at #4000. Specifically, #4000 is the control port, and #4004 is the write port.

I setup the driver to map to these and navigate to the output test screen and fire off the sound test. It works! I hear a 'ping' sound just like my original hardware. Its not exact, but I'm sure its due to the improper frequency I setup for the cpu.

I know that I can mess with the sound settings in operator mode in a page further down, so I advance the pages but cannot get to the sound screen. There is probably a variable in memory that needs to be set in order to let it know that that page is available.

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