I have a simple design which pipes the input of one of the ADC16 channels to the 1GbE block to be recorded on an external computer. The clock input for the ROACH board is set to 200MHz and there is a 20MHz, 20mVp-p, AC coupled input to channel A1 of the ADC (verified on an oscilloscope). Reading the values sent across the 1GbE, I get the following:
255 255 255 255 255 0 0 0 0 0 255 255 255 255 255 0 0 0 0 0 Which looks like the ADC is saturating, however, the CASPER documentation indicates that the full scale input of the ADC is 2V p-p. For reference, I have successfully transferred counter data through the ethernet port, so I know that this interface is capable of transferring values besides x00 and xFF. Does anyone have suggestions as to how to fix this problem? -Joe Kujawski
