This is a Bally AS-2518-51 sound board, the predecessor of the Squawk & Talk implemented in an FPGA. This is set up with the ROM for the 1978 pinball Nitro Ground Shaker but other ROMs are available. http://ipdb.org/showpic.pl?id=1682&picno=37007
Some general info about the hardware http://zerocharactersleft.blogspot.com/2014/07/retro-pinball-reverse-engineering-bally.html
This one is interesting because it uses a AY-3-8910 sound synthesis chip to generate all the sounds rather than driving a DAC directly from the PIA. It’s got a bit of a different sound as a result.
It has not been tested in an actual pinball. Currently it is set up to plug in a PS/2 Keyboard that will allow you to trigger all of the sounds. Some keys are repeats, others are blank, it was just a quick hack. The PS/2 hack is in the top level file and easy to remove which would theoretically allow you to wire this up in a real pinball.
The target board for this is the very economical Altera Cyclone II dev board. They are all over eBay for less than $20.
Here is the code:
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