Dear Nordic Support,
I am using PPI to link 2 timers (10ms & 5s) with 2 SAADC channel (AIN1 - channel 0 & AIN2 - channel 1).
The nrf_drv_saadc_init function is only called once so it means there is only one callback for the sampling event. In case I am using 2 channels, how do I know that which channel has completed its sampling event in the callback function? When I printed out the ADC value, all I saw is CH0 and CH1 are read at the same time while I expect CH0 every 10ms and CH1 every 5s.
I am using nRF52840 + nRF5 SDK 15.3 + SD 6.1.1.
Thank you and best regards,
Duy
void saadc_transducer_callback(nrf_drv_saadc_evt_t const * p_event) { uint8_t idx; if (p_event->type == NRF_DRV_SAADC_EVT_DONE) { APP_ERROR_CHECK(nrf_drv_saadc_buffer_convert(p_event->data.done.p_buffer, RAW_ADC_BUFF_SIZE)); NRF_LOG_INFO("T.ADC event number: %d", (int)m_transducer_evt_counter); for (idx = 0; idx < RAW_ADC_BUFF_SIZE; idx++) { NRF_LOG_INFO("%d", p_event->data.done.p_buffer[idx]); } m_transducer_evt_counter++; } } static void saadc_sampling_event_init(void) { uint32_t transducer_timer_compare_event_addr, battery_timer_compare_event_addr; uint32_t saadc_sample_task_addr; APP_ERROR_CHECK(nrf_drv_ppi_init()); nrf_drv_timer_enable(&TRANSDUCER_TIMER); nrf_drv_timer_enable(&BATTERY_TIMER); transducer_timer_compare_event_addr = nrf_drv_timer_compare_event_address_get(&TRANSDUCER_TIMER, NRF_TIMER_CC_CHANNEL0); battery_timer_compare_event_addr = nrf_drv_timer_compare_event_address_get(&BATTERY_TIMER, NRF_TIMER_CC_CHANNEL0); saadc_sample_task_addr = nrf_drv_saadc_sample_task_get(); /* Setup ppi channel so that timer compare event is triggering sample tasks in SAADC */ APP_ERROR_CHECK(nrf_drv_ppi_channel_alloc(&TORQUE_SAADC_TIMER_PPI_CHANNEL)); APP_ERROR_CHECK(nrf_drv_ppi_channel_alloc(&BATTERY_SAADC_TIMER_PPI_CHANNEL)); APP_ERROR_CHECK(nrf_drv_ppi_channel_assign(TORQUE_SAADC_TIMER_PPI_CHANNEL, transducer_timer_compare_event_addr, saadc_sample_task_addr)); APP_ERROR_CHECK(nrf_drv_ppi_channel_assign(BATTERY_SAADC_TIMER_PPI_CHANNEL, battery_timer_compare_event_addr, saadc_sample_task_addr)); } static void saadc_init(void) { nrf_saadc_channel_config_t adc_channel_config = NRF_DRV_SAADC_DEFAULT_CHANNEL_CONFIG_SE(NRF_SAADC_INPUT_AIN1); nrf_saadc_channel_config_t battery_channel_config = NRF_DRV_SAADC_DEFAULT_CHANNEL_CONFIG_SE(NRF_SAADC_INPUT_AIN2); APP_ERROR_CHECK(nrf_drv_saadc_init(NULL, saadc_transducer_callback)); APP_ERROR_CHECK(nrf_drv_saadc_channel_init(0, &adc_channel_config)); APP_ERROR_CHECK(nrf_drv_saadc_channel_init(1, &battery_channel_config)); APP_ERROR_CHECK(nrf_drv_saadc_buffer_convert(m_buffer_pool[0], RAW_ADC_BUFF_SIZE)); APP_ERROR_CHECK(nrf_drv_saadc_buffer_convert(m_buffer_pool[1], RAW_ADC_BUFF_SIZE)); }
Hi,
If you want one SAADC channel to run every 5ms, and another to run every 5 seconds, you need to use two timers.
This is because the timer itself will not count to 5 ms, fire the event for sampling your first channel, then run for another 4.995 seconds before triggering the event to sample your second channel.
Could you try to run a individual timer per event and see if that works better?
Kind regards,
Håkon
Hello Håkon Alseth,
Thank you for your answer, I am running 2 different timers running in different periods (10ms and 5s). If I run only 1 ADC channel + 1 TIMER with PPI, everything works fine.
Warm regards,
#define APP_ADV_INTERVAL 32 /**< The advertising interval (in units of 0.625 ms. This value corresponds to 25 ms). */ #define ADC_ACQUISITION_INTERVAL 10 #define BATTERY_LEVEL_MEAS_INTERVAL 10000 /**< Battery level measurement interval (ticks). */ #define APP_ADV_DURATION 18000 /**< The advertising duration (180 seconds) in units of 10 milliseconds. */ static void saadc_init(void) { nrf_saadc_channel_config_t adc_channel_config = NRF_DRV_SAADC_DEFAULT_CHANNEL_CONFIG_SE(NRF_SAADC_INPUT_AIN1); nrf_saadc_channel_config_t battery_channel_config = NRF_DRV_SAADC_DEFAULT_CHANNEL_CONFIG_SE(NRF_SAADC_INPUT_AIN2); APP_ERROR_CHECK(nrf_drv_saadc_init(NULL, saadc_transducer_callback)); // APP_ERROR_CHECK(nrf_drv_saadc_init(NULL, saadc_battery_callback)); APP_ERROR_CHECK(nrf_drv_saadc_channel_init(0, &adc_channel_config)); APP_ERROR_CHECK(nrf_drv_saadc_channel_init(1, &battery_channel_config)); APP_ERROR_CHECK(nrf_drv_saadc_buffer_convert(m_buffer_pool[0], RAW_ADC_BUFF_SIZE)); APP_ERROR_CHECK(nrf_drv_saadc_buffer_convert(m_buffer_pool[1], RAW_ADC_BUFF_SIZE)); } /**@brief Function for the Timer initialization. * * @details Initializes the timer module. This creates and starts application timers. */ static void timers_init(void) { nrf_drv_timer_config_t timer_cfg = NRF_DRV_TIMER_DEFAULT_CONFIG; /* Enable app timer */ APP_ERROR_CHECK(app_timer_init()); /* Create ADC timer */ APP_ERROR_CHECK(nrf_drv_timer_init(&TRANSDUCER_TIMER, &timer_cfg, adc_acquisition_timeout_handler)); nrf_drv_timer_extended_compare(&TRANSDUCER_TIMER, NRF_TIMER_CC_CHANNEL0, nrf_drv_timer_ms_to_ticks(&TRANSDUCER_TIMER, ADC_ACQUISITION_INTERVAL), NRF_TIMER_SHORT_COMPARE0_CLEAR_MASK, true); /* Configure BATTERY TIMER */ APP_ERROR_CHECK(nrf_drv_timer_init(&BATTERY_TIMER, &timer_cfg, battery_level_meas_timeout_handler)); nrf_drv_timer_extended_compare(&BATTERY_TIMER, NRF_TIMER_CC_CHANNEL0, nrf_drv_timer_ms_to_ticks(&BATTERY_TIMER, BATTERY_LEVEL_MEAS_INTERVAL), NRF_TIMER_SHORT_COMPARE0_CLEAR_MASK, true); } static void saadc_sampling_event_init(void) { uint32_t transducer_timer_compare_event_addr, battery_timer_compare_event_addr; uint32_t saadc_sample_task_addr; APP_ERROR_CHECK(nrf_drv_ppi_init()); nrf_drv_timer_enable(&TRANSDUCER_TIMER); nrf_drv_timer_enable(&BATTERY_TIMER); transducer_timer_compare_event_addr = nrf_drv_timer_compare_event_address_get(&TRANSDUCER_TIMER, NRF_TIMER_CC_CHANNEL0); battery_timer_compare_event_addr = nrf_drv_timer_compare_event_address_get(&BATTERY_TIMER, NRF_TIMER_CC_CHANNEL0); saadc_sample_task_addr = nrf_drv_saadc_sample_task_get(); /* Setup ppi channel so that timer compare event is triggering sample tasks in SAADC */ APP_ERROR_CHECK(nrf_drv_ppi_channel_alloc(&TORQUE_SAADC_TIMER_PPI_CHANNEL)); APP_ERROR_CHECK(nrf_drv_ppi_channel_alloc(&BATTERY_SAADC_TIMER_PPI_CHANNEL)); APP_ERROR_CHECK(nrf_drv_ppi_channel_assign(TORQUE_SAADC_TIMER_PPI_CHANNEL, transducer_timer_compare_event_addr, saadc_sample_task_addr)); APP_ERROR_CHECK(nrf_drv_ppi_channel_assign(BATTERY_SAADC_TIMER_PPI_CHANNEL, battery_timer_compare_event_addr, saadc_sample_task_addr)); }