Hi Ziming, It appear that the controller is sending the NAK to the device in the logic capture frames you provided. It only is expecting one 8-bit data frame from the device, and a NAK tells the device to stop outputting conversion data. Because of this, you are not reading in the full conversion. You will need to configure the controller to read in more than 1 byte before sending a NAK, but I don't know how to accomplish this with your specific command line tool. 1. Due to the condition above where the controller sends a premature NAK, I will say that this sequence is not meeting the requirements, and you will need to change the controller configuration as mentioned to read in at least 2 bytes of data at a time, as 1 ADC conversion is encoded across 2 bytes. 2. At the moment, no. The full 12-bit conversion is encoded across 2-bytes. The first byte contains the first 8 bits of ADC data (D[11:4]), and the next byte contains D[3:0], followed by 4 zeroes at the end by default. I do believe we are getting closer to the desired result, and the logic captures are very helpful in debugging this. Please continue sending logic captures, and I can help further. Regards, Joel
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