SAADC,NRF52832,How to calculata accurate sampling interval

RE: SAADC,NRF52832,How to calculata accurate sampling interval

Carsten Wulff — Wed, 31 May 2017 05:22:11 GMT

You have to use a timer or the MCU to trigger 2kS/s samplerate. There is no other alternative inside the SAADC.

RE: SAADC,NRF52832,How to calculata accurate sampling interval

suker — Wed, 31 May 2017 01:34:00 GMT

3,How to control a 2k/s sampling?

RE: SAADC,NRF52832,How to calculata accurate sampling interval

suker — Wed, 31 May 2017 01:14:39 GMT

1,can I change 16M? 2,I want to achive 2K/S sampling

RE: SAADC,NRF52832,How to calculata accurate sampling interval

suker — Wed, 31 May 2017 01:13:43 GMT

I want to do a real time sampling and transport data used ESB. I don't want to add a timer.because I think i can used connect a NRF_SAADC->EVENTS_END to NRF_SAADC->TASKS_SAMPLE.

RE: SAADC,NRF52832,How to calculata accurate sampling interval

Carsten Wulff — Sun, 28 May 2017 15:01:01 GMT

You do indeed have time for oversampling. Oversampling will reduce the noise levels by 1/sqrt(2) for each increment of OVERSAMPLE, assuming the noise is white.

The way you've setup the PPI above will give you the max sample rate (tack + tconv).

Use an event from a timer as the EEP. Also, what was the purpose of forking start? I don't think you need to do that.

RE: SAADC,NRF52832,How to calculata accurate sampling interval

Carsten Wulff — Sat, 27 May 2017 19:03:49 GMT

The maximum value of the samplerate register is 2047, so for samplerates below 16Mhz/2047 you must use PPI and a Timer.

RE: SAADC,NRF52832,How to calculata accurate sampling interval

suker — Sat, 27 May 2017 06:01:56 GMT

What is the diffrence of oversampling and burst mode? whis mode is suit for me? I want to do a adc with 2K/S sampling.

RE: SAADC,NRF52832,How to calculata accurate sampling interval

suker — Sat, 27 May 2017 05:44:36 GMT

I want to do a sample rate at 2K/S, and used PPI

void ppi_init()
{
/************************* START SAMPLING ON SAADC EVENTS_END *************************/
NRF_PPI->CH[4].EEP = (uint32_t)&NRF_SAADC->EVENTS_END;
NRF_PPI->CH[4].TEP = (uint32_t)&NRF_SAADC->TASKS_SAMPLE;
NRF_PPI->FORK[4].TEP = (uint32_t)&NRF_SAADC->TASKS_START;
NRF_PPI->CHEN |= PPI_CHENSET_CH4_Enabled << PPI_CHENSET_CH4_Pos;
}

for connect NRF_SAADC->EVENTS_END to NRF_SAADC->TASKS_START ,then it will sample all the time . but how to control sample interval?