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Why getting zero values from EVAL-AD7656-1SDZ in serial mode?

Hello team,

I want to interface between EVAL-AD7656-1SDZ and STM32L4R5ZI-P using normal SPI but I'm not getting data, I got zero.

Here I'm using serial interface mode so I held a high SER/PEL SEL pin.

I used the following pins-

RD, WR, CS, REFEN, RESET, BUSY, CONVST pins as GPIO pin interface with ours MCU.

Steps which I followed for interface to ADC-

1) RD pin high.

2) WR pin low.

3) CS pin low.

4) REFEN pin High.

5) WR pin high.

6)  RD pin low.

7) Deinit GPIO of REFEN,  because DB9 is connected to DOUTB and as per the datasheet this pin should be unconnected.

8) CS pin high

9)  CONVST pin high

10) RESET pin low

11) RESET pin high

12) RESET pin low

After this init SPI

For reading ADC data use the following steps-

1) CONVST pin low, delay 1us

2) CONVST pin high, delay 3us

3) Check the BUSY pin, if pin status is low then go for the next steps

4) CS pin low 

5)  Read data on one DOUT line for this transfer of 96 clocks.

6) CS pin high

I want to read data from DOUTA and I pulsed all three conversion lines. here I connected SDATA_A to MISO, SDATA_B, SDATA_C, and MOSI  line is unconnected.

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[edited by: yash.rayak at 5:12 AM (GMT -4) on 13 Jul 2021]

Moved your thread to Precision ADC community. Someone here might be able to answer your query.