This thread has been locked.

If you have a related question, please click the "Ask a related question" button in the top right corner. The newly created question will be automatically linked to this question.

ADS127L21EVM-PDK: How is the startup sequence for L21 different from L11

Part Number: ADS127L21EVM-PDK
Other Parts Discussed in Thread: ADS127L11, ADS127L21

Tool/software:

I would like to evaluate a custom driver I have written for ADS127L21 on the basis of example code for ADS127L11. Some of the registers are significantly different, however. Could someone recommend a bare bones startup sequence that would work for L21? Would it be something like:

- Initialize SPI on controller device (SPI Mode 1, MSB first)

- Set Reset pin high

- Set Start pin high

- Toggle reset?

Would it be possible to then communicate with the ADC in 4 wire SPI mode to test reading/writing register values and data without CRC verificaiton, assuming we are satisfied with the default settings?
Is it possible to leave the PHI controller plugged in for power supply while we're communicating with the ADC evm board over the exposed SPI pins?

  • Hello Tetiana,

    Welcome to the TI E2E community.

    Yes, the above sequence you outlined will work well, but you do not need to toggle the reset after setting the START pin high.  Once START is high, the ADC will start continuously converting data at the power-up default settings of 512ksps.

    No, you will not be able to leave the PHI controller connected and use an external controller board.  You can power the ADS127L21EVM by connecting a +6V supply to the GND/+Vin pins of J12 (regulated to +5V on the EVM) and an IO supply voltage to J13 (this supply is directly connected to the ADS127L21, and should be between 1.8V to 5V nominal depending on your IO voltages from your MCU board).  In order to use external power, you will also need to move jumper JP4 to the +Vin position.

    Also, the PHI board provides the clock source to the ADS127L21.  Using the ADS127L21EVM board without the PHI connected, you will also need to move jumper JP7 to the EVM/EXT CLK position.

    Regards,
    Keith Nicholas
    Precision ADC Applications