Jeri Reverse Engineers an HC55564 Chip from an Old Pinball Machine

Gareth Branwyn

Gareth Branwyn is a freelance writer and the former Editorial Director of Maker Media. He is the author or editor of over a dozen books on technology, DIY, and geek culture. He is currently a contributor to Boing Boing, Wink Books, and Wink Fun. And he has a new best-of writing collection and "lazy person's memoir," called Borg Like Me.

3989 Articles

By Gareth Branwyn

Gareth Branwyn is a freelance writer and the former Editorial Director of Maker Media. He is the author or editor of over a dozen books on technology, DIY, and geek culture. He is currently a contributor to Boing Boing, Wink Books, and Wink Fun. And he has a new best-of writing collection and "lazy person's memoir," called Borg Like Me.

3989 Articles

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In her latest Intersil “Academy of Analog Pinball Wizardry” video, Jeri Ellsworth replaces an HC55564 Continuous Variable Slope Delta (CVSD) codec chip with one she reversed engineered into an FPGA. What in blue-blazes is a CVSD modulator? Watch the vid and find out — as usual, Jeri does a great job of showing how it works, how she reversed engineered it, and what the results are. As some have pointed out, you can still scare these chips up online, but this was more about proving and showing than just about fixing.

Continuous Variable Slope Delta Modulator – HC55564