EDIT I think there is somewhere in KEIL or nrf libraries a bad pointer type alignement .
The correct pointer is given as uint_32_t (NRF_SAADC->RESULT.PTR = (uint32_t)&adcr;) but the result buffer uint32_t adcr[] is composed in this way :
ADCR[0] -> 2_high_byte=AIN1 value ---- 2_low_bytes=AIN0 value
ADCR[1] -> 2_high_byte=AIN3 value ---- 2_low_bytes=AIN2 value
ADCR[2] -> 2_low_bytes=AIN4 value
It's an uint_16_t type result .
So if I use 32 bit cast to a 16 bit buffer , I find the correct values in uint_16_t adcr[].
I don't know if it's a Keil or libraries issue , but with this workaround I'm able to read all 5 Analog input .
Maurizio
Hello , I'trying to read 5 analog channels AIN0 to AIN4 with nRF52 on BMD300 module . With the same configuration for each channel I'm able to read in buffer ADCR[] chanells 0,1,2 and 3 , but I read always 0(zero) on channel 4 . What's wrong ?
BMD300 module + S212 0.9.1 + SDK 11
Thanks
static void adc_init(void)
{
NRF_COMP->ENABLE= 0;
NRF_LPCOMP->ENABLE = 0;
// Start HFCLK from crystal oscillator, this will give the SAADC higher accuracy LFCLKSTART
NRF_CLOCK->TASKS_HFCLKSTART = 1;
while (NRF_CLOCK->EVENTS_HFCLKSTARTED == 0);
NRF_CLOCK->EVENTS_HFCLKSTARTED = 0;
// Configure SAADC singled-ended channel, Internal reference (0.6V) and 1/6 gain.
NRF_SAADC->CH[0].CONFIG = (SAADC_CH_CONFIG_GAIN_Gain1_6 << SAADC_CH_CONFIG_GAIN_Pos) |
(SAADC_CH_CONFIG_MODE_SE << SAADC_CH_CONFIG_MODE_Pos) |
(SAADC_CH_CONFIG_REFSEL_Internal << SAADC_CH_CONFIG_REFSEL_Pos) |
(SAADC_CH_CONFIG_RESN_Bypass << SAADC_CH_CONFIG_RESN_Pos) |
(SAADC_CH_CONFIG_RESP_Bypass << SAADC_CH_CONFIG_RESP_Pos) |
(SAADC_CH_CONFIG_TACQ_20us << SAADC_CH_CONFIG_TACQ_Pos);
NRF_SAADC->CH[1].CONFIG = (SAADC_CH_CONFIG_GAIN_Gain1_6 << SAADC_CH_CONFIG_GAIN_Pos) |
(SAADC_CH_CONFIG_MODE_SE << SAADC_CH_CONFIG_MODE_Pos) |
(SAADC_CH_CONFIG_REFSEL_Internal << SAADC_CH_CONFIG_REFSEL_Pos) |
(SAADC_CH_CONFIG_RESN_Bypass << SAADC_CH_CONFIG_RESN_Pos) |
(SAADC_CH_CONFIG_RESP_Bypass << SAADC_CH_CONFIG_RESP_Pos) |
(SAADC_CH_CONFIG_TACQ_20us << SAADC_CH_CONFIG_TACQ_Pos);
NRF_SAADC->CH[2].CONFIG = (SAADC_CH_CONFIG_GAIN_Gain1_6 << SAADC_CH_CONFIG_GAIN_Pos) |
(SAADC_CH_CONFIG_MODE_SE << SAADC_CH_CONFIG_MODE_Pos) |
(SAADC_CH_CONFIG_REFSEL_Internal << SAADC_CH_CONFIG_REFSEL_Pos) |
(SAADC_CH_CONFIG_RESN_Bypass << SAADC_CH_CONFIG_RESN_Pos) |
(SAADC_CH_CONFIG_RESP_Bypass << SAADC_CH_CONFIG_RESP_Pos) |
(SAADC_CH_CONFIG_TACQ_20us << SAADC_CH_CONFIG_TACQ_Pos);
NRF_SAADC->CH[3].CONFIG = (SAADC_CH_CONFIG_GAIN_Gain1_6 << SAADC_CH_CONFIG_GAIN_Pos) |
(SAADC_CH_CONFIG_MODE_SE << SAADC_CH_CONFIG_MODE_Pos) |
(SAADC_CH_CONFIG_REFSEL_Internal << SAADC_CH_CONFIG_REFSEL_Pos) |
(SAADC_CH_CONFIG_RESN_Bypass << SAADC_CH_CONFIG_RESN_Pos) |
(SAADC_CH_CONFIG_RESP_Bypass << SAADC_CH_CONFIG_RESP_Pos) |
(SAADC_CH_CONFIG_TACQ_20us << SAADC_CH_CONFIG_TACQ_Pos);
NRF_SAADC->CH[4].CONFIG = (SAADC_CH_CONFIG_GAIN_Gain1_6 << SAADC_CH_CONFIG_GAIN_Pos) |
(SAADC_CH_CONFIG_MODE_SE << SAADC_CH_CONFIG_MODE_Pos) |
(SAADC_CH_CONFIG_REFSEL_Internal << SAADC_CH_CONFIG_REFSEL_Pos) |
(SAADC_CH_CONFIG_RESN_Bypass << SAADC_CH_CONFIG_RESN_Pos) |
(SAADC_CH_CONFIG_RESP_Bypass << SAADC_CH_CONFIG_RESP_Pos) |
(SAADC_CH_CONFIG_TACQ_20us << SAADC_CH_CONFIG_TACQ_Pos);
// Configure the SAADC resolution.
NRF_SAADC->RESOLUTION = SAADC_RESOLUTION_VAL_12bit << SAADC_RESOLUTION_VAL_Pos;
// Configure result to be put in RAM at the location of "result" variable.
NRF_SAADC->RESULT.MAXCNT = 5;
NRF_SAADC->RESULT.PTR = (uint32_t)&adcr;
// No automatic sampling, will trigger with TASKS_SAMPLE.
NRF_SAADC->SAMPLERATE = SAADC_SAMPLERATE_MODE_Task << SAADC_SAMPLERATE_MODE_Pos;
// Enable SAADC (would capture analog pins if they were used in CH[0].PSELP)
NRF_SAADC->ENABLE = SAADC_ENABLE_ENABLE_Enabled << SAADC_ENABLE_ENABLE_Pos;
NRF_SAADC->CH[0].PSELP = SAADC_CH_PSELP_PSELP_AnalogInput0 << SAADC_CH_PSELP_PSELP_Pos; // Collego POS a ANALOG INPUT 0
NRF_SAADC->CH[0].PSELN = SAADC_CH_PSELN_PSELN_NC << SAADC_CH_PSELN_PSELN_Pos; // Collego NEG a GND (Single ended)
NRF_SAADC->CH[1].PSELP = SAADC_CH_PSELP_PSELP_AnalogInput1 << SAADC_CH_PSELP_PSELP_Pos; // Collego POS a ANALOG INPUT 1
NRF_SAADC->CH[1].PSELN = SAADC_CH_PSELN_PSELN_NC << SAADC_CH_PSELN_PSELN_Pos; // Collego NEG a GND (Single ended)
NRF_SAADC->CH[2].PSELP = SAADC_CH_PSELP_PSELP_AnalogInput2 << SAADC_CH_PSELP_PSELP_Pos; // Collego POS a ANALOG INPUT 2
NRF_SAADC->CH[2].PSELN = SAADC_CH_PSELN_PSELN_NC << SAADC_CH_PSELN_PSELN_Pos; // Collego NEG a GND (Single ended)
NRF_SAADC->CH[3].PSELP = SAADC_CH_PSELP_PSELP_AnalogInput3 << SAADC_CH_PSELP_PSELP_Pos; // Collego POS a ANALOG INPUT 3
NRF_SAADC->CH[3].PSELN = SAADC_CH_PSELN_PSELN_NC << SAADC_CH_PSELN_PSELN_Pos; // Collego NEG a GND (Single ended)
NRF_SAADC->CH[4].PSELP = SAADC_CH_PSELP_PSELP_AnalogInput4 << SAADC_CH_PSELP_PSELP_Pos; // Collego POS a ANALOG INPUT 4
NRF_SAADC->CH[4].PSELN = SAADC_CH_PSELN_PSELN_NC << SAADC_CH_PSELN_PSELN_Pos; // Collego NEG a GND (Single ended)
}
