• State TI Thinks Resolved
  • Locked Locked
  • Replies 5 replies
  • Answers 1 answer
  • Subscribers 47 subscribers
  • Views 778 views
  • Users 0 members are here
Support feedback
Options
Options
Related

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.

WCT on ADS1298 breaks data ready

Tilen Majerle
Prodigy 70 points
Other Parts Discussed in Thread: ADS1298

Hello,

I'm using ADS1298 for ECG measurements. Everything works fine, data ready is set to 1kHz, except when I add config for WCT1 and WCT2 registers, data ready is triggered only once where I read data as normal and never again.

What could be the reason for that? Am I missing something?

My WCT configs are this:

WCT1: 0x0D

WCT2: 0xC4

Electrodes set for WCTA,B and C are correct set. I don't know why this is happening.

Thanks for any answer.

  • 0
    TI__Mastermind 18285 points
    Tilen,

    I am moving your post to the correct forum.
  • 0
    TI__Mastermind 38745 points
    Hey Tilen,

    My theory is that you are accidentally doing something that will stop conversions. Are you able to read registers from the device after this occurs? Check your SPI protocol for those register writes on the scope or a logic analyzer to make sure those things are happening as you expect.

    Regards,
    Brian Pisani
  • 0 in reply to Brian Pisani
    Prodigy 70 points
    To be honest, I'm thinking right now that my ADS chip got blown somehow.
    I noticed, that when ECG is running and if I want to change gain for input channels, I do this:

    STOP conversions
    Change gain
    START again,

    and if there is gain other than 6 (defaul value) again, DRDY pin is not getting low and data are not ready.

    Tomorrow I will solder another board to test if there is problem with blown chip or something else.

    Anyway, thanks for help.
  • 0 in reply to Brian Pisani
    Prodigy 70 points

    Hello again,

    I've soldered another board with new ADS chip and without setting WCT registers.

    It started working as expected, but then, I set bit WCT_TO_RLD in CONFIG4 register and again, everything stops working.

    So, one board has set WCT1 and WCT2 registers and not set bit WCT_TO_RLD in CFG4, another board has WCT1 and WCT2 not set but has WCT_TO_RLD set to 1. In both cases, it does not work nothing.

    Then, I removed all WCT related settings from my init code and from there, there is no data ready anymore. So I blow up somehow 2 chips. 

    Both chips respond to ID register and I read them OK, but data ready is not set for more than 30 times.

    So, there must  be something strange with chip?

    I have also added in my code that if ECGH should be active and if there is not data ready for more than 20ms, I send OP_START again but there is still never data ready.

    I have attached my ADS schematics where you can check.

  • 0 in reply to Tilen Majerle
    TI__Mastermind 38745 points
    Hey Tilen,

    Do the devices continue to convert following a reset? Your schematic looks ok. Would you mind sending me all of the register data you are able to read back after the device seems to stop working?

    Regards,
    Brian Pisani