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  • TI Thinks Resolved

AM5728: SPI4 read data error

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Replies: 6

Views: 171

Part Number: AM5728

Customer has problem on using AM5726 SPI4. the returned read data is always wrong, the wave shows data is right from external sensor, but wrong in SPI module.

Send out read ID command, sensor returned the right ID value 0x12, but in SPI_rx register it is 0x0186. 

Customer has verified I2C, CAN, UART, UART, SPI1, SPI2, QSPI on the AM5726 board made by themselves. but SPI4 has the issue.

As either GPEVM nor IDK did not connect device on SPI4, I don't know how to verify. Please help.

Regards. Tony Tang
  • Hi,

    Which Processor SDK are you using?

    Best Regards,
    Yordan

     


     Please make sure you read the forum guidelines first.

  • In reply to Yordan Kovachev:

    Yordan,

    customer is using: processor_sdk_rtos_am57xx_5_01_00_11

    They tested on both ARM side with Linux and DSP side with PDK RTOS example, both have the same issue.

    Regards. Tony Tang
  • In reply to Tony Tang:

    Hi Tony,

    Can they try with different PHA, POL settings in the CHxCONF register (as described in the TRM, MCSPI chapter)?

    Best Regards,
    Yordan

     


     Please make sure you read the forum guidelines first.

  • In reply to Yordan Kovachev:

    Yordan,

     The register setting in the picture, did you see any wrong according to the timing wave form?

    Regards. Tony Tang
  • In reply to Yordan Kovachev:

    Yordan,

    Figured out the issue due to a 22pf capacitor in the data line. remove it, data is right. but can't explain as scoped on both side of the resistor, same wave form, why different result.

    Regards. Tony Tang
  • In reply to Tony Tang:

    Hi Tony,

    I am not sure why you use such connection between the sensor & AM5726 SoC. You do not need the capacitor, neither we have such recommendation in the datasheet. Also the serial resistor.. you could have it on the clk line (maybe 51 ohm are a bit much) if the sensor requires it, but this is not recommended in the AM5726 datasheet.

    Best Regards,
    Yordan

     


     Please make sure you read the forum guidelines first.

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