UCD3138A64: Requesting help using EADC in SAR mode

I appreciate the response.

I added your register settngs exactly to the code, but it did not solve my issue;  I am still getting all zeros in the EADCVALUE register.

I must be missing something subtle, but necessary.
Besides the EADCCNTL and the SARCNTL registers is there any thing else needed.
(As I mentioned in my first message, DPWM0 is operating at 200KHz.)

Thank you.

Hello,

The expert is out of office. Will come to you when he's back.

Best Regards,

Xuemei

I am using Front End 1, so LoopMuxRegs.SAMPTRIGCTRL.bit.FE1_TRIG_DPWM0_EN = 1

I made some changes and I am finally getting some values in ABS_VALUE.
The last change which produced results in ABS_VALUE was changing SAMP_TRIG_SCALE from 1 to 15.
As I mentioned earlier, I am sample triggering off of DPWM0 at 200KHz.

Is it possible that the SAR takes longer than 5 microseconds to run?
If so, how fast can it be run?

The counts in ABS_VALUE are consistently low even as I change the DC test voltage to various levels during testing.

Is it possible that the the SAR is not completing and I am reading an intermediate result from ABS_VALUE?
Is there a flag which indicates SAR calculation is done?

Thanks for the help,

-Craig

what value is used in the below register?

Dpwm1Regs.DPWMSAMPTRIG1.all

SAR has short time than 5us to finish conversion.

I haven't seen SAR is not completed as long as EAD is triggered.

Sorry for the delay.  I am having CCS problems.

I am not using DPWM1
I should be triggering off of DPWM0.

Dpwm0Regs.DPWMSAMPTRIG1.all = 1664.

I borrowed the code, but I believe the intent was to trigger near the falling edge of DPWM0A; DPM0A pulse width may be very short at this moment.

At this moment, it should not matter where the trigger occurs because the EADC is connected to the output of a current sensor which is being fed a constant current.

Please use smaller Dpwm0Regs.DPWMSAMPTRIG1.all , such as 50.

Thank you for the suggestion.  I am working remote today.  I will be in the lab Mnday morning and will try it then.

I am getting results, but they are still reading low.

I need to check with the hardware designer about scaling resistors in the analog circuit.

I appreciate all the help.  I may try a method other than SAR to get calculate the analog signal value.

I'm going to leave this thread open for a few days in case there is a follow-up.

Thank you again.