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ADS1291: ADS1291 AFE4404 Simultaneous Measurement

kim minseo
Intellectual 400 points
Part Number: ADS1291
Other Parts Discussed in Thread: AFE4404,

Hi.

I am developing with afe4404 and ads1291.

I want to measure AFE4404 and ADS1291 at the same time.

I set AFE4404 to 120Hz and ADS1291 to 500Hz.

I know that the number of data is different because the Hz is different, but it's okay because I'm going to look at it based on time.

When I tested it, I checked that 4 to 5 ECG data came in when 1 PPG data came in according to Hz.

However, both PPG and ECG data are coming in well, but the ECG data stops reading in the middle and only PPG data comes in.

  • Part Number
    1 - PPG
    2 - ECG
  • When you collect 5 pieces of data and check them, Even if the Hz is different, the data comes out normally. (PPG - 5, ECG - 20)
  • But over time, the number of ECG data decreases, and only PPG data comes out.

Is it impossible to measure simultaneously if the Hz is different?

Thank you.

  • 0
    TI__Mastermind 19815 points

    Hi,

    May I ask for more clarification about "I am developing with afe4404 and ads1291."?

    E.g. How do you connect your host with each of them? what topology? How are the SPI lines from each slave connected to the host/master?

    ------------------------------

    Extend from the question above -

    Could you explain/elaborate more on "4 to 5 ECG data came in when 1 PPG data came in according to Hz."?

    ------------------------------

    What host/master or computer software and How did you have those number displayed?  Are they printed from any multi-thread or concurrency codes? If yes, the odder/sequence they are displayed may not represent the same/correct order/sequence they are received.

    ----------------

    What are the units of both reading shown -

    1 - PPG

    2 - ECG

    in voltage or ADC count/code?

    ----------------------------------------------------------

    Need clarification and more explanation on this - "

    • When you collect 5 pieces of data and check them, Even if the Hz is different, the data comes out normally. (PPG - 5, ECG - 20)"?

    --------------------------------------

    Have you tried working with each device individually and independently, and make sure each device works properly expected individually and independently? 

    Thanks

  • 0 in reply to ChienChun Yang
    Intellectual 400 points

    Hi. Thank you for your reply.

    ChienChun Yang said:
    E.g. How do you connect your host with each of them? what topology? How are the SPI lines from each slave connected to the host/master?

    I am using nRF52832.

    AFE4404 is connected to I2C and ADS1291 is connected to SPI.

    AFE4404 - ADC_RDY
    ADS1291 - DRDY
    I connect that part with an interrupt.

    Whenever RDY was ready to interrupt, I counted and checked.

    ChienChun Yang said:
    in voltage or ADC count/code?

    Both ADC count/code.

    ChienChun Yang said:
    Have you tried working with each device individually and independently, and make sure each device works properly expected individually and independently? 

    PPG data measurement was carried out normally with the AFE4404 chip.

    ECG data measurement was carried out normally with ADS1291 chip.

    I had a problem combining the two functions.

    Thank you.

  • 0 in reply to kim minseo
    TI__Mastermind 19815 points

    Hi,

    So, does each device have different and independent 

    SCLK vs SCL  lines?

    MISO,MOSI vs SDA lines?

    CS line for SPI only?

    -------------------------------------------------------------------------- 

    You may want to check the firmware code to see how the data are streaming in to host/master? e.g. how the data reading is scheduled & arranged? what order and sequence and how are they interleaved? any conflict?

    If you would like to share the schematic. we can take a look. If schematic cannot be disclosed in public, please let me know, I can reach out to you via email.

    Thanks