The Apple II’s CPU clock has jitter or a glitch. This issue is not new—it has been present since its original design in 1977! Bald Engineer uses an oscilloscope to show how often the glitch occurs and how to correlate that jitter to its source—which is useful when you are not testing 40-year-old devices. The device under test (DUT) in this video is the Mega IIe project. It’s a fully compatible Apple IIe built around the Mega II chip.
Related Links
- [archive.org] Understanding the Apple IIe
- [archive.org] The Apple II Circuit
- [google.com] Apple II Clock Spreadsheet
- [youtube.com] Mega IIe Project Video
- [mirrors.apple2.org.za] David Empson Explaining Video Cycles
