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FaradayRF / FaradayRF-Hardware

Faraday hardware design files
https://www.faradayrf.com
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Remove AVCC RC Filter And Low Frequency Crystal #20

Closed kb1lqc closed 7 years ago

kb1lqc commented 8 years ago

The ADC AVCC filter isn't really needed, just keep the decoupling capacitor. We never really use the low frequency watch crystal X1 (32.768 KHz). Should DNP that.

Testing

kb1lqc commented 8 years ago

R17 removed

kb1lqc commented 8 years ago

Tested Faraday with HAB Flight software/Firmware with R17 removed/shorted, worked fine as expected. Leaving AVCC decoupling capacitor on.

kb1lqc commented 8 years ago

Removed C7 and C8 without what appears to be any affect. Hard to measure frequency with an oscilloscope probe as it appears to be pretty low amplitude and the probe will likely be affecting the signal anyways. Would be best to use a counter internal to the CC430 to check this frequency but @kb1lqd says there are internal capacitors that can help mitigate issues we see. I'll DNP instead of removing anyways.

To test this we could just count the cycles based on X1 and divide by 32768, then trigger an IO pin. If we are anywere near 1Hz edges then this is pretty spot on.

kb1lqc commented 7 years ago

Moved to RevD, DNPd:

kb1lqc commented 7 years ago

Also removed AVCC filter resistor: