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A project log for Симон

The old "Simon" memory game.... with an evil twist

nick-sayerNick Sayer 08/16/2019 at 20:400 Comments

One problem I didn’t catch with the prototype until very late is that playing a sound glitches the controller. The issue likely is that the sudden power draw from the audio amplifier destabilizes the 3.3v bus. This wasn’t an issue with the GPS talking clock because the amplifier there was run from 5 volts, so the 3.3v LDO served to protect the logic system from the transients. 

For this project I tried adding more bypass capacitance to the controller, but it didn’t help. So I’ll try adding some decoupling inductance in front of the amplifier. I’ll happily accept power instability there as opposed to on the controller’s supply.

The other issue I’ve discovered is that noise from the LED rastering is making it into the audio. Hopefully just routing the audio line so that it doesn’t cross under any of the raster lines will be enough (which was not the case on the prototype).

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