> The chip has 3 pins, but there are 8 pads on the die. The other pins appear to be used for testing. By activating one of the pins, the chip can be put into a

> The chip has 3 pins, but there are 8 pads on the die. The other pins appear to be used for testing. By activating one of the pins, the chip can be put into a test mode. The test mode runs through the songs at 512× speed so the chip can be tested quickly without waiting for the tunes to play. The other test pins appear to expose other internal data for testing. This makes me wonder if you put one of the other test pins on a scope, if you'd see a pattern representing the song or sequence, allowing quick verification of the chip. I think at 512x speed, even a more limited storage scope of the era of these chips could capture the full output on-screen. Each flavor of the chip probably had an expected pattern based on ROM which could be checked. I'm imagining a technician sitting at a test bench, having to do verification work on these all day, thankful for having a test pin instead of having to listen to the same dang beeping song over and over :)