I'm using the Teensy to do FFT on an audio signal and send out SPI data to digital pots (MCP41010).
I had it working on a breadboard for a while and finally got around to making a nice, durable, PCB version of it.
Its a simple project but since putting it to PCB it has been acting very inconsistently, and I've been stumped as to why.
Today, I was investigating the problem by experimenting with termination resistors for the input signal path and measuring various points on the board. This yielded me no insights but I did accidentally briefly short out the Vref pad to GND once and after that it performed much better. Similarly, I briefly shorted the 3.3V pin to GND and it did the same thing.
I'm using a 28-pin IC socket to connect the teensy to the PCB. The only thing I can think of is that the socket is creating stray capacitance at Vin that effects the other voltage pins (vref and 3.3v). Does this make sense or am I way off?
Any other ideas about what could be going on?
Thank you.
I had it working on a breadboard for a while and finally got around to making a nice, durable, PCB version of it.
Its a simple project but since putting it to PCB it has been acting very inconsistently, and I've been stumped as to why.
Today, I was investigating the problem by experimenting with termination resistors for the input signal path and measuring various points on the board. This yielded me no insights but I did accidentally briefly short out the Vref pad to GND once and after that it performed much better. Similarly, I briefly shorted the 3.3V pin to GND and it did the same thing.
I'm using a 28-pin IC socket to connect the teensy to the PCB. The only thing I can think of is that the socket is creating stray capacitance at Vin that effects the other voltage pins (vref and 3.3v). Does this make sense or am I way off?
Any other ideas about what could be going on?
Thank you.
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