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A project log for NEDONAND homebrew computer

NEDONAND is 8-bit homebrew computer entirely built out of many 74F00 chips (2-input NAND gates)

SHAOSSHAOS 03/10/2016 at 05:572 Comments

Just put together NEDONAND-3 with 2 NEDONAND-2 and NEDONAND-16 ROM "programmed" with 4-bit to Hex converter to display 4-bit address in human readable format:

This is ROM alone (I drilled a few holes and installed 7-segment indicator directly on the board):

Discussions

Yann Guidon / YGDES wrote 03/10/2016 at 09:23 point

Negative logic, I see :-)

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SHAOS wrote 03/10/2016 at 15:23 point

Yes, because LEDs must be connected between power and TTL outputs to work properly with TTL so all lights are inverted - then I used diodes for "zeros" instead of "ones" (it's actually less diodes in this case ; )

P.S. In true ROM application with the same board it will be diodes for "ones" though...

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