SAADC Easy DMA with 1 Channel

RE: SAADC Easy DMA with 1 Channel

radioschmadio — Mon, 03 Apr 2017 16:01:37 GMT

Duhhhhhhhhhhh. Works fine now.

RE: SAADC Easy DMA with 1 Channel

Jørgen Holmefjord — Mon, 03 Apr 2017 08:52:36 GMT

Do you call NVIC_EnableIRQ(SAADC_IRQn); in your code to register the peripheral with the interrupt controller? I would also recommend that you check out this example, which is written by one of my colleagues. You can change it to run continuously by doing the changes as described in this thread.

RE: SAADC Easy DMA with 1 Channel

radioschmadio — Fri, 31 Mar 2017 15:42:09 GMT

So, for some reason it started working, but for some reason I can not get the interrupt to trigger to do another sample. I would like it to continuously sample the one channel. I enabled all the interrupts and still nothing.

RE: SAADC Easy DMA with 1 Channel

radioschmadio — Fri, 31 Mar 2017 15:37:28 GMT

uint32_t adc_results[1024]={0};

void setup_adc() { NRF_SAADC ->ENABLE = 0;

	NRF_SAADC ->RESOLUTION = 2 ; //12 bit resolution
	NRF_SAADC ->OVERSAMPLE = 0; //bypass over sampling

	NRF_SAADC ->RESULT.PTR = (uint32_t)&adc_results[0];
	NRF_SAADC ->RESULT.MAXCNT = 512; 
	NRF_SAADC ->SAMPLERATE= 0x000010FF;  //fast sample rate auto 

	NRF_SAADC ->CH[0].CONFIG = 	(SAADC_CH_CONFIG_BURST_Disabled << SAADC_CH_CONFIG_BURST_Pos) | \
															(SAADC_CH_CONFIG_MODE_SE << SAADC_CH_CONFIG_MODE_Pos ) | \
															(SAADC_CH_CONFIG_TACQ_10us << SAADC_CH_CONFIG_TACQ_Pos ) | \
															(SAADC_CH_CONFIG_REFSEL_Internal << SAADC_CH_CONFIG_REFSEL_Pos) | \
															(SAADC_CH_CONFIG_GAIN_Gain1_6 << SAADC_CH_CONFIG_GAIN_Pos ) | \
															(SAADC_CH_CONFIG_RESN_Bypass << SAADC_CH_CONFIG_RESN_Pos ) | \
															(SAADC_CH_CONFIG_RESP_Bypass << SAADC_CH_CONFIG_RESP_Pos ) ;

	NRF_SAADC ->CH[0].LIMIT = 0;
	NRF_SAADC ->CH[0].PSELN = 0;
	NRF_SAADC ->CH[0].PSELP = 2;

	NRF_SAADC ->INTEN = 0x0000000E ; //enable int for end
	NRF_SAADC ->ENABLE = 1;
	NRF_SAADC ->TASKS_START = 1;

}

void start_adc() {

//NRF_SAADC ->TASKS_START = 1;
NRF_SAADC ->TASKS_SAMPLE = 1;

}

void SAADC_IRQHandler (void) {

NRF_SAADC ->INTEN = 0x00000000 ; //disable int for end
NRF_SAADC ->EVENTS_END = 0; //clear event
NRF_SAADC ->EVENTS_DONE = 0; //clear event
NRF_SAADC ->EVENTS_RESULTDONE = 0; //clear event
//NRF_SAADC ->TASKS_START = 1;
    //NRF_SAADC ->TASKS_SAMPLE = 1;
NRF_SAADC ->RESULT.PTR = (uint32_t)&adc_results[0];
NRF_SAADC ->INTEN = 0x00000002 ; //enable int for end

}

RE: SAADC Easy DMA with 1 Channel

Jørgen Holmefjord — Fri, 31 Mar 2017 09:40:34 GMT

Do you mean that you have a buffer with a size > 1, and you only get one sample in the buffer? Could you post some code showing how you do sampling?