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Last Updated: 2023-06-03 The Electronic Machine for Multiple Applications, Version 1 EMMA-1 is a super-general-purpose system designed to be a "workbench" computer that can be modified to do whatever is needed for a project. It features a 65C02, power-on-reset generator, no memory, no ROM, no clock generation, and no power supply. (It's basically a 65C02 with expansion connectors). The simple design was indended to make it easy to add or modify whatever circuitry is needed for a particular project. More specifically, the ultimate goal was to use this as a development system for the fabled GUI computer's hardware. The trouble with this plan was that the system was so generic that "feature paralysis" set in and I did not design any cards besides a NOP generator to check the CPU. With so many options, it was hard to decide what I should or should not add and how one card might affect a possible future card that I had not even thought of yet. Definetly something to be learned here about maintaining project scope. The PCB itself was designed using the free version of Eagle 7.4.0. The astute reader might notice that in the photos below, the board is much larger than the 100x80mm (?) limitation of the free version. At the time I did this design, I had gotten pretty handy at modifying the board files in a text editor to get around the limitations of the free version. It would interestingly still allow traces to be routed outside of the limitation area. This meant that I just had to do component placement in the text editor and I was able to complete the routing within Eagle.


EMMA-1 shown with one expansion card inserted. The card contains a clock oscillator and a set of resistors to pull the CPU's data bus to $EA (NOP).


The much more powerful upgrade to EMMA-1! EMMA-2
That's all!
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