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AM6421: Interfacing ADS131m08 to Am6421, dummy response from MCSPI module

shraddha naik
Intellectual 440 points

Part Number: AM6421
Other Parts Discussed in Thread: ADS131M04, , ADS131M08, SYSCONFIG

Hi,

I had interfaced ADS131M04 with AM6421 and code was working fine here. Same code with minimal change (mentioned below) done as per ADS131M08, i am not getting the expected response from ADC.

All my SPI module & other gpios are exactly kept same for m04 & m08

Code modified for M08

  1. Channel count changed to 8- So that device id changes to 0x28 

As troubleshooting steps:

  1. I have checked SCLK pin- frequecy is as expected
  2. Ocillator freq to ADS board is correct as expected.

On initialization i get below frames:

NOTE: Not able to upload any images

But when i send wakeup or standby command, response is not as expected

Anything i missed or any other changes i need to modify when migrating to ADS131M08? 

Regards

Shraddha Naik

  • 0
    TI__Guru 58125 points

    Hi,

    Please refer the datasheet for ADS131M04 and ADS131M08 and check for differences if any.

    If this is taken care of, then there should not be any issue with the xxx08 ADS.

    I would have you check the MCSPI connections in SysConfig as well, refer this:  [FAQ] SK-AM64B: MCSPI Integration Guide 

    Check things like if the Reset pin is connected or not, and other hardware connections as well.

    If none of the above works out for you, please share the code for interfacing both the variants of ADS.

    BR Vaibhav

  • 0 in reply to Vaibhav Kumar
    Intellectual 440 points

    Hi,

    I have interfaced our custom board with ADS131M04 and code is working fine. Same custom board interfaced with ADS131M08, (WIth channel count changed to 8) i am able to read the register but Write single register doesnt work here. What can be the issue here?

    Write Clock reg with 0xFF06

    Response of Write Reg

    Read back Clock reg

    Response of Read Reg: it reads default value 0xFF0E

    For M08, its mentioned we need to send 10 words so I also tried changing dataTx & dataRx buffer to 30bytes(10 words) but getiing same response.

    Regards,

    Shraddha

  • 0 in reply to shraddha naik
    Intellectual 440 points

    If i read STATUS register, i get default value

  • 0 in reply to shraddha naik
    TI__Guru 58125 points

    Thank you for the update.

    I believe Dale is reviewing the same, but apart from that I have not yet received the code configurations. I would need the MCSPI Configurations in the main.c or the application.c file.

    Looks like it would mostly be HW issue but just to rule out the SW configuration, I would like you to share how the MCSPI parameters have been defined. In your code, this would be actually the parameters just after MCSPI_Transaction_init and before MCSPI_transfer calls.

    Looking forward to it.

    Best regards,

    Vaibhav

  • 0 in reply to Vaibhav Kumar
    Intellectual 440 points

    HI Vaibhav,

    Currently i am using TIs  API calls for MCSPI transfer, I know we need to optimize the code & also need to make the data size 24bit, since this code was tested earlier with 8bit datasize with ADS131M04 i did not change anything wrt SPI configuration afterwards.

    this is my send command code snippet

    As ADC configuration,

    I just toggle the ADC sync/rest pin for 2ms, and then try to read the register & write clock & mode register. Any other configuration i need to do ?

    Regards

    Shraddha

  • 0 in reply to shraddha naik
    Intellectual 440 points

    Hi Vaibhav,

    Any SPI configuration change is required?

  • 0 in reply to shraddha naik
    TI__Guru 58125 points

    Hi,

    I am reviewing the changes you have shared.

    Allow me sometime, meanwhile I will also compare the M04 and M08 datasheet.

    Thanks,

    Vaibhav

  • 0 in reply to shraddha naik
    TI__Guru 58125 points

    Hi,

    You can start by checking the following.

    After resetting for 2 ms, are you waiting for another 10 microseconds? Please make sure you do this, as this ensures tREGACQ. This would imply that the registers are stable and ready for SPI Communication.

    Here is what I read in the ADS datasheet for RESET:

    Although the value of tREGACQ is 5 microseconds(as mentioned in the datasheet), put a sleep of 10 microseconds for margin in your code just after RESET.

    Additionally are you reading the ID register to confirm the ID 0x2800 for M08 variant? Please let me know. This would ensure the connection with ADSxxM08 is properly established.

    Looking forward to your response.

    Best regards,

    Vaibhav

    Best regards,

    Vaibhav