OSI Superboard II Replicated

While our modern computer can easily emulate a lot of different old machines, there is something about having replica hardware that is even better. Not as nice as having the real thing, in some ways, although you don’t have to worry about wear and tear on a replica, either. [Jeff Tranter] has built a kit replica of an Ohio Scientific Superboard II, and it looks great, as you can see in the video below.

This was an inexpensive all-in-one 6502 computer with a keyboard and provision for TV or monitor output. If you had a 5V power supply, a cassette deck, and a TV you were in business for less money than most of the comparable alternatives. In fact, [Jeff] has the canceled check where his parents paid $486 Canadian for one in 1981. That was his introduction to computing, and we’d say that was a reasonable investment on the part of his parents.

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A Teensy Logic Analyzer For A 6502

[John] has an interesting, if old piece of tech sitting on his workbench. It’s an Ohio Scientific C3-8P computer from the late 70s by way of a few garages, basements, and attics. As with most tech of this vintage, there are some problems, and [John] found debugging a little frustrating without the ability to trace and watch the programs. He needed a logic analyzer, and found one in an unlikely piece of hardware. [John] built one using a Teensy microcontroller, and further refinement of this project could turn it into a full in-system emulator.

The old Ohio Scientific computer [John] is trying to bring back from the dead is based on the 6502 CPU. That’s sixteen address lines to monitor, eight data lines, and four control lines. These were wired directly to a Teensy 3.1.

Reading and controlling all the signals from a 6502 is a task that falls to Linux. A command line program controls the Teensy and is capable of reading memory, setting trigger addresses, dumping the entire address space to a file, or just recording the last 5,000 clock cycles. This kind of tech existed back in the late 70s and early 80s. It also cost a fortune. Now, with a $20 Teensy and probably another $30 in ribbon cables and test clips, anyone can build a logic analyser for a very old computer system.

Videos below.

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