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A sturdy Tiny302 prototype

A project log for Tiny302

A homebrew minimal 68302-based SBC

PlasmodePlasmode 01/13/2018 at 15:330 Comments

I found a couple MC68302 in PGA package buried in my junk piles. So I constructed a more rugged Tiny302 prototype to experiment with. It is certainly a better looking prototype.  It is the same design with 8-bit wide data bus using 128Kx8 Flash and 128Kx8 RAM so the existing monitor/debugger runs on it as is. Running at 16MHz with zero-wait memory, it's performance is roughly that of a 8MHz 68K with 16-bit wide bus. Except for a few SMT bypass caps, this is a thru-hole design, down to a dozen or so of discrete carbon resistors. I plan to build EASy68K's 7-segment/LED/push button hardware on the remaining prototype area using the same thru-hole component technology.

The schematic of the prototype is done using a very old tool, IVEX's Windraft. IVEX is no longer in business, but I've purchased the license for both schematic and board layout tools a long time ago. Windraft seems to run OK in Windows Vista, but the version of Winboard I have needs to run on older WIndows operating system. If anyone knows how to get Winboard to run in newer Windows, please let me know.

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