CWLite and UFO board, using external AWG clock signal


I know this is similar to my last thread, but I thought I would start a new one to get the header more specific to the question.

I want to use an arbitrary waveform generator to provide an external clock to the UFO and CWLite boards (I’m having an oscilloscope in parallel, and want to synchronize the whole system). However, I can’t get it to work. The AWG outputs a 10 MHz square wave from 0 to 3V. I have set the jumper settings on J3 so as to “pretend” to be the crystal oscillator. I have connected the square waveform to pin 2 (no jumper though), and a jumper on HS1 (pins 3-4). The scope.clock settings are

scope.clock.adc_src = 'extclk_x1'
scope.clock.extclk_freq = 10000000 
target.baud = target.baud*(10/7.37)

but the output becomes


I got this to work with the external oscillator, btw. Any idea what might be wrong? Has anyone else successfully used an external AWG clock source?


It might be helpful to verify that the target is alive? You can do this different ways, for example:

  1. with an external debugger
  2. modify the target firmware so it outputs something when it starts, and look for that output, either with a simpleserial read, or with an external logic analyzer.

Once you’ve confirmed that the target is alive and well, then you can move on to figuring whether it’s responding to commands from your host, etc…