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trouble with communication of ADXL362 and STM32F4

Question asked by hnxyxiaomeng on Jul 30, 2018
Latest reply on Jul 30, 2018 by jwang

   I used an STM32F4 evaluation board to communicate with ADXL362(i.e., official EVAL-ADXL362Z evaluation board). The program was improved based on an example offered by the STM32F4 evaluation board developers, which run correctly with an SPI FLASH chip.

       Before reading the FIFO data, the DEVID_AD was read. But the result was 0X91 although the expected was 0XAD.

The state of pin CS was set to low before SPI communication while set to high after communication, and this was ensured on the basis of waveform.

       The data sequence sent to ADXL362 was based on the datasheet, i.e., read command(0X0B), DEVID_AD address(0X00), a dummy byte(0XAA was chosen). The waveforms of SCLK and MOSI(send to ADL362) captured by oscilloscope were pasted as follows.

         In my opinion, the waveforms were correctly , right?



    However, the waveforms of SCLK and MISO(send from ADXL362 while ADXL362 receiving the data sequence) were very weird. They were pasted as follows:



errrrrr..... The result was 0X91,not 0XAD.

Can someone help me analyze why this happens?