I have the schematic finished now. I checked the major critical paths to the VRAM, fining one that was too slow. The VRAM takes up to 55ns from address input to data output, and I have only 62.5ns, so really it is super close. Since the uPD7220 uses an address latching mechanism, I managed to move my address-modifying critical path to before this latching is done. The timing there is much more forgiving. Other than that, I added some pretty LEDs and checked/fixed some of the logic done in the circuit.I may add more decoupling capacitors still, but that isn't a real design change. The capacitors are the only SMD components I'm using.
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