Rev 4 of the SN76489 sound board and Game Controller board are ready with a few tweaks to improve usability.

SN76489 Rev 4

Rev 4 adds a built-in 3.58MHz clock so that tones generated by the sound chip are independent of the bus speed.  This improves compatibility with Z180-based systems where the clock speed would otherwise be too fast for the sound chip.  In addition, to prevent random tones from playing before the sound chip is initialized, a flip flop blocks the clock from reaching the sound chip until the first write is made to initialize the chip. Asserting the reset line will reset the flip flop again and stop the clock.  Additional jumpers are also added to fully decode A0 and A1 so a single address can be specified.

Game Controller Rev 4

Rev 4 allows the on-board numeric buttons to be used for both Player 1 and Player 2 where before they could only be used by Player 1.  This change also prevents directional input from Player 2 from being erroneously interpreted as numeric input when using a non-Coleco controller.  In addition, the button footprints have been changed to better fit standard tactile buttons.