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ADS1292R: Test Signal Not Received from ADS1292R

Dinu
Intellectual 335 points
Part Number: ADS1292R

Hi Friends


ADS1292R EVM Board purchased from TI. I have seen ECG output waveform with your controller(MSP430) in Desktop system with provided software. Now we are trying to interface ADS1292R with our own controller (LPC1788 Cortex M3). We are facing an issue to display the test signals. I am unable to get the Test signal data in ADS1292R. But I can read Device ID through SPI communication (10MHz).

Below List Configuration of software and Hardware (what we tried)
1. We are choosing Internal clock For ADS1292R(in Hardware ->Clock Selection Pin as Pull up)
2. The RESET Pin Always Pull up (in Hardware)
3. In Hardware Start Pin didn't used (Start Command used in Software)
4. Register configuration For Test Signal
CONFIG 1 =2(0x02)
CONFIG 2 =163(0xA3)
LOFF =16
CH1SET =5
CH2SET =5
RLD_SENS =0
LOFF_SENS =0
LOFF_STAT =0
RESP1 =2
RESP2 =1

Please guide us, if any configurations corrections or any other changes. Thanks in Advance.


Regards,

Dinu

  • 0
    TI__Guru 66186 points
    Hello Dinu,

    Your register settings look fine. Do you see /DRDY pulsing at the set data rate? You should see /DRDY transition from high to low every 2ms for 500 SPS.

    Since you are not using the START pin, make sure it is tied low to DGND. Also, upon start-up, it is important to issue a /RESET pulse after the tPOR timing has passed. After configuring your registers, you will need need to send the START command to begin conversions and the RDATAC command to read data automatically after each new /DRDY. For more information, please see Figure 63: Initial Flow at Power-Up in the datasheet.

    Best Regards,
  • 0 in reply to Ryan Andrews
    Intellectual 335 points
    Hi Ryan Andrews,

    Thanks for the Reply.

    I can read device id address(0x20) and I catch the 115 decimal value in ADS1292R. The SPI communication in between ADS1292R and our application Processor(LPC1788) is Ok in above condition.

    After configuration is completed, I saw DRDY transition from high to low every 2ms for 500 SPS but data is not received in test signal.

    I have studied the Figure 63 in ADS1292R datasheet and I'd follow what the figure say, But test signal is not received .

    When I send START command I did see one high low transition in data ready(DRDY) pin and I send RDATAC Command then DRDY Pin is always high. So I didn't Get data samples. help me to resolve this issue.



    Below List Configuration of software and Hardware (what we tried)
    1. We are choosing Internal clock For ADS1292R(in Hardware ->Clock Selection Pin as Pull up)
    2. The RESET Pin Always Pull up (in Hardware)
    3. In Hardware Start Pin didn't used (Start Command used in Software)
    4. Register configuration For Test Signal
    CONFIG 1 =2(0x02)
    CONFIG 2 =163(0xA3)
    LOFF =16
    CH1SET =5
    CH2SET =5
    RLD_SENS =0
    LOFF_SENS =0
    LOFF_STAT =0
    RESP1 =2
    RESP2 =1
  • 0 in reply to Dinu
    TI__Guru 66186 points

    Hello Dinu,

    What is the state of the START pin on your board? If you plan to control the conversions with SPI commands, the START pin should be tied low to DGND through a resistor.

    I would like to confirm some details after each step in your start-up sequence:

    1. After power-up, send SDATAC. Do you send SDATAC?
    2. Send RESET.
    3. Write all register configurations. Do you read all register values back to confirm they are correct?
    4. Send the START command to begin conversions. After tSETTLE, does /DRDY toggle continuously at the set data rate?
    5. Send RDATAC. /DRDY should continue to toggle, does it stop?
    6. Activate the SPI interface (/CS = 0) and send 72 SCLKs to read data each time you detect /DRDY transitioning from high to low.

    The register settings you listed above are correct.

    Best Regards,

  • 0 in reply to Ryan Andrews
    Intellectual 335 points
    Hello Ryan Andrews

    Thanks for the reply.Now my problem is resolved.