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Problem reading data out of AD7606C-18

Hi,

I am trying to interface EVAL-AD7606CFMCZ to a Raspberry Pi Pico. I am having problem reading data out of the ADC. For a start, I tried reading the register address 0x2F which should return 0x31 for my board. But it is returning 0x00 (when CPHA is set to 0 which, from datasheet, I think is the setting that must be used) and 0x32 (when CPHA is set to 1. I was doubtful. So checked this too). I have attached two images, one with CPOL=0 and the other with CPOL=1, showing signals from DoutA (Green color signal in image), SCLK (Yellow). SDI (Purple) and CSn (Blue) pins.

I have written 0b01 10 1111 as suggested in the datasheet, to read the 0b101111 (0x2f) register. I am getting 0b00110010 (0x32). I should be getting 0b00110001 (0x31).


Fig.1 DoutA (Green), SCLK (Yellow). SDI (Purple) and CSn (Blue) when CPOL=1 and CPHA=1


Fig.2 DoutA (Green), SCLK (Yellow). SDI (Purple) and CSn (Blue) when CPOL=1 and CPHA=0

Please let me know if I have misunderstood anything or if I have done something wrongly.

Thanks.



Updated the signal bits
[edited by: Srivamsi at 11:58 AM (GMT -4) on 19 Jul 2021]