I am using two SAADC channel on nRF52 DK, one for pressure sensor and another for battery level. I realized 0.5mA is higher than single channel. Is it normal?
void saadc_init(void)
{
ret_code_t err_code;
nrf_drv_saadc_config_t saadc_config;
nrf_saadc_channel_config_t channel_config;
//Configure SAADC
saadc_config.low_power_mode = true; //Enable low power mode.
saadc_config.resolution = NRF_SAADC_RESOLUTION_10BIT; //Set SAADC resolution to 12-bit. This will make the SAADC output values from 0 (when input voltage is 0V) to 2^12=4096 (when input voltage is 3.6V for channel gain setting of 1/6).
saadc_config.oversample = SAADC_OVERSAMPLE; //Set oversample to 4x. This will make the SAADC output a single averaged value when the SAMPLE task is triggered 4 times.
saadc_config.interrupt_priority = APP_IRQ_PRIORITY_LOW; //Set SAADC interrupt to low priority.
//Initialize SAADC
err_code = nrf_drv_saadc_init(&saadc_config, saadc_callback_handler); //Initialize the SAADC with configuration and callback function. The application must then implement the saadc_callback function, which will be called when SAADC interrupt is triggered
APP_ERROR_CHECK(err_code);
//Configure SAADC channel
channel_config.reference = NRF_SAADC_REFERENCE_INTERNAL; //Set internal reference of fixed 0.6 volts
channel_config.gain = NRF_SAADC_GAIN1_6; //Set input gain to 1/6. The maximum SAADC input voltage is then 0.6V/(1/6)=3.6V. The single ended input range is then 0V-3.6V
channel_config.acq_time = NRF_SAADC_ACQTIME_10US; //Set acquisition time. Set low acquisition time to enable maximum sampling frequency of 200kHz. Set high acquisition time to allow maximum source resistance up to 800 kohm, see the SAADC electrical specification in the PS.
channel_config.mode = NRF_SAADC_MODE_SINGLE_ENDED; //Set SAADC as single ended. This means it will only have the positive pin as input, and the negative pin is shorted to ground (0V) internally.
if(SAADC_BURST_MODE)
{
channel_config.burst = NRF_SAADC_BURST_ENABLED; //Configure burst mode for channel 0. Burst is useful together with oversampling. When triggering the SAMPLE task in burst mode, the SAADC will sample "Oversample" number of times as fast as it can and then output a single averaged value to the RAM buffer. If burst mode is not enabled, the SAMPLE task needs to be triggered "Oversample" number of times to output a single averaged value to the RAM buffer.
}
channel_config.pin_p = NRF_SAADC_INPUT_AIN5; //Select the input pin for the channel. AIN0 pin maps to physical pin P0.02.
channel_config.pin_n = NRF_SAADC_INPUT_DISABLED; //Since the SAADC is single ended, the negative pin is disabled. The negative pin is shorted to ground internally.
channel_config.resistor_p = NRF_SAADC_RESISTOR_DISABLED; //Disable pullup resistor on the input pin
channel_config.resistor_n = NRF_SAADC_RESISTOR_DISABLED; //Disable pulldown resistor on the input pin
//Initialize SAADC channel
err_code = nrf_drv_saadc_channel_init(0, &channel_config); //Initialize SAADC channel 0 with the channel configuration
APP_ERROR_CHECK(err_code);
err_code = nrf_drv_saadc_buffer_convert(m_buffer_pool[0],SAMPLE_BUFFER_LEN); //Set SAADC buffer 1. The SAADC will start to write to this buffer
APP_ERROR_CHECK(err_code);
err_code = nrf_drv_saadc_buffer_convert(m_buffer_pool[1],SAMPLE_BUFFER_LEN); //Set SAADC buffer 2. The SAADC will write to this buffer when buffer 1 is full. This will give the applicaiton time to process data in buffer 1.
APP_ERROR_CHECK(err_code);
// ret_code_t err_code;
// nrf_drv_saadc_config_t saadc_config;
// nrf_saadc_channel_config_t channel_0_config, channel_1_config;
//
//
// //Configure SAADC
// saadc_config.low_power_mode = true; //Enable low power mode.
// saadc_config.resolution = NRF_SAADC_RESOLUTION_10BIT; //Set SAADC resolution to 12-bit. This will make the SAADC output values from 0 (when input voltage is 0V) to 2^12=4096 (when input voltage is 3.6V for channel gain setting of 1/6).
// saadc_config.oversample = SAADC_OVERSAMPLE; //Set oversample to 4x. This will make the SAADC output a single averaged value when the SAMPLE task is triggered 4 times.
// saadc_config.interrupt_priority = APP_IRQ_PRIORITY_LOW; //Set SAADC interrupt to low priority.
//
// //Initialize SAADC
// err_code = nrf_drv_saadc_init(&saadc_config, saadc_callback_handler); //Initialize the SAADC with configuration and callback function. The application must then implement the saadc_callback function, which will be called when SAADC interrupt is triggered
// APP_ERROR_CHECK(err_code);
//
// //Configure SAADC channel 0
// channel_0_config.reference = NRF_SAADC_REFERENCE_INTERNAL; //Set internal reference of fixed 0.6 volts
// channel_0_config.gain = NRF_SAADC_GAIN1_6; //Set input gain to 1/6. The maximum SAADC input voltage is then 0.6V/(1/6)=3.6V. The single ended input range is then 0V-3.6V
// channel_0_config.acq_time = NRF_SAADC_ACQTIME_10US; //Set acquisition time. Set low acquisition time to enable maximum sampling frequency of 200kHz. Set high acquisition time to allow maximum source resistance up to 800 kohm, see the SAADC electrical specification in the PS.
// channel_0_config.mode = NRF_SAADC_MODE_SINGLE_ENDED; //Set SAADC as single ended. This means it will only have the positive pin as input, and the negative pin is shorted to ground (0V) internally.
// if(SAADC_BURST_MODE)
// {
// channel_0_config.burst = NRF_SAADC_BURST_ENABLED; //Configure burst mode for channel 0. Burst is useful together with oversampling. When triggering the SAMPLE task in burst mode, the SAADC will sample "Oversample" number of times as fast as it can and then output a single averaged value to the RAM buffer. If burst mode is not enabled, the SAMPLE task needs to be triggered "Oversample" number of times to output a single averaged value to the RAM buffer.
// }
// channel_0_config.pin_p = NRF_SAADC_INPUT_AIN5; //Select the input pin for the channel. AIN0 pin maps to physical pin P0.02.
// channel_0_config.pin_n = NRF_SAADC_INPUT_DISABLED; //Since the SAADC is single ended, the negative pin is disabled. The negative pin is shorted to ground internally.
// channel_0_config.resistor_p = NRF_SAADC_RESISTOR_DISABLED; //Disable pullup resistor on the input pin
// channel_0_config.resistor_n = NRF_SAADC_RESISTOR_DISABLED; //Disable pulldown resistor on the input pin
//
// //Configure SAADC channel 1
// channel_1_config.reference = NRF_SAADC_REFERENCE_INTERNAL; //Set internal reference of fixed 0.6 volts
// channel_1_config.gain = NRF_SAADC_GAIN1_6; //Set input gain to 1/6. The maximum SAADC input voltage is then 0.6V/(1/6)=3.6V. The single ended input range is then 0V-3.6V
// channel_1_config.acq_time = NRF_SAADC_ACQTIME_10US; //Set acquisition time. Set low acquisition time to enable maximum sampling frequency of 200kHz. Set high acquisition time to allow maximum source resistance up to 800 kohm, see the SAADC electrical specification in the PS.
// channel_1_config.mode = NRF_SAADC_MODE_SINGLE_ENDED; //Set SAADC as single ended. This means it will only have the positive pin as input, and the negative pin is shorted to ground (0V) internally.
// if(SAADC_BURST_MODE)
// {
// channel_1_config.burst = NRF_SAADC_BURST_ENABLED; //Configure burst mode for channel 0. Burst is useful together with oversampling. When triggering the SAMPLE task in burst mode, the SAADC will sample "Oversample" number of times as fast as it can and then output a single averaged value to the RAM buffer. If burst mode is not enabled, the SAMPLE task needs to be triggered "Oversample" number of times to output a single averaged value to the RAM buffer.
// }
// channel_1_config.pin_p = NRF_SAADC_INPUT_VDD; //Select the input pin for the channel. AIN0 pin maps to physical pin P0.02.
// channel_1_config.pin_n = NRF_SAADC_INPUT_DISABLED; //Since the SAADC is single ended, the negative pin is disabled. The negative pin is shorted to ground internally.
// channel_1_config.resistor_p = NRF_SAADC_RESISTOR_DISABLED; //Disable pullup resistor on the input pin
// channel_1_config.resistor_n = NRF_SAADC_RESISTOR_DISABLED; //Disable pulldown resistor on the input pin
//
//
// //Initialize SAADC channel 0
// err_code = nrf_drv_saadc_channel_init(0, &channel_0_config); //Initialize SAADC channel 0 with the channel configuration for PS
// APP_ERROR_CHECK(err_code);
//
// //Initialize SAADC channel 1
// err_code = nrf_drv_saadc_channel_init(1, &channel_1_config); //Initialize SAADC channel 1 with the channel configuration for BAT
// APP_ERROR_CHECK(err_code);
//
// err_code = nrf_drv_saadc_buffer_convert(m_buffer_pool[0],SAMPLE_BUFFER_LEN); //for ch0 pressure sensor
// APP_ERROR_CHECK(err_code);
//
// err_code = nrf_drv_saadc_buffer_convert(m_buffer_pool[1],SAMPLE_BUFFER_LEN); //for ch1 battery check
// APP_ERROR_CHECK(err_code);
}
