Hi, I am new to nordic n51822, i have implemented adc and timer independently. Now, what i want to do is read the adc values on a specific time when the timer overflows for 500ms. I am little confused that void ADC_IRQHandler(void) continually polls and reads the value and displays the value on UART. Can anyone guide me through the steps on how to read adc with specific time, like when enabling timing interrupt timer starts and reads value and every time when the value is read , the interrupt is stopped and values are processed then again the interrupt is activated and timer is started. What i want is to create a specific sample rate in which it reads adc,process values,print and repeat.
#define UART_TX_BUF_SIZE 256 /**< UART TX buffer size. */
#define UART_RX_BUF_SIZE 1 /**< UART RX buffer size. */
#define GPIO_TOGGLE_PIN 4 /*!< gpio pin to toggle after delay. */
#ifndef NRF_APP_PRIORITY_HIGH #define NRF_APP_PRIORITY_HIGH 1
#endif
/** @TIMER2
*
*
*/
void start_timer(void)
{
NRF_TIMER2->MODE = TIMER_MODE_MODE_Timer; // Set the timer in Counter Mode
NRF_TIMER2->TASKS_CLEAR = 1; // clear the task first to be usable for later
NRF_TIMER2->PRESCALER = 8; //Set prescaler. Higher number gives slower timer. Prescaler = 0 gives 16MHz timer
NRF_TIMER2->BITMODE = TIMER_BITMODE_BITMODE_16Bit; //Set counter to 16 bit resolution
NRF_TIMER2->CC[0] = 31250; //Set value for TIMER2 compare register 0
// Enable interrupt on Timer 2, both for CC[0] and CC[1] compare match events
NRF_TIMER2->INTENSET = (TIMER_INTENSET_COMPARE0_Enabled << TIMER_INTENSET_COMPARE0_Pos) ;
//| (TIMER_INTENSET_COMPARE1_Enabled << TIMER_INTENSET_COMPARE1_Pos);
NVIC_EnableIRQ(TIMER2_IRQn);
NRF_TIMER2->SHORTS = (TIMER_SHORTS_COMPARE0_CLEAR_Enabled << TIMER_SHORTS_COMPARE0_CLEAR_Pos) & TIMER_SHORTS_COMPARE0_CLEAR_Msk;
NRF_TIMER2->TASKS_START = 1; // Start TIMER2
}
/** TIMTER2 peripheral interrupt handler. This interrupt handler is called whenever there it a TIMER2 interrupt
*/
void TIMER2_IRQHandler(void)
{
if(NRF_TIMER2->EVENTS_COMPARE[0])
{
NRF_TIMER2->EVENTS_COMPARE[0] = 0; //Clear compare register 0 event
nrf_gpio_pin_toggle(GPIO_TOGGLE_PIN);
}
}
/**
* @brief UART events handler.
*/
void uart_events_handler(app_uart_evt_t * p_event)
{
switch (p_event->evt_type)
{
case APP_UART_COMMUNICATION_ERROR: APP_ERROR_HANDLER(p_event->data.error_communication);
break;
case APP_UART_FIFO_ERROR: APP_ERROR_HANDLER(p_event->data.error_code);
break;
case APP_UART_TX_EMPTY: printf("RESULT= %1.1f\r\n", (float)adc_sample); // out ADC result
break;
default: break;
}
}
/**
* @brief ADC interrupt handler.
*/
void ADC_IRQHandler(void)
{
nrf_adc_conversion_event_clean();
adc_sample = nrf_adc_result_get();
// trigger next ADC conversion
nrf_adc_start();
}
/**
* @brief UART initialization.
*/
void uart_config(void)
{
uint32_t err_code;
const app_uart_comm_params_t comm_params =
{
RX_PIN_NUMBER,
TX_PIN_NUMBER,
RTS_PIN_NUMBER,
CTS_PIN_NUMBER,
APP_UART_FLOW_CONTROL_DISABLED,
false,
UART_BAUDRATE_BAUDRATE_Baud38400
};
APP_UART_FIFO_INIT(&comm_params,
UART_RX_BUF_SIZE,
UART_TX_BUF_SIZE,
uart_events_handler,
APP_IRQ_PRIORITY_LOW,
err_code);
APP_ERROR_CHECK(err_code);
}
/**
* @brief ADC initialization.
*/
void adc_config(void)
{
const nrf_adc_config_t nrf_adc_config = NRF_ADC_CONFIG_DEFAULT;
// Initialize and configure ADC
nrf_adc_configure( (nrf_adc_config_t *)&nrf_adc_config);
nrf_adc_input_select(NRF_ADC_CONFIG_INPUT_7);
nrf_adc_int_enable(ADC_INTENSET_END_Enabled << ADC_INTENSET_END_Pos);
//ADC INTERRUPT ENABLE
NVIC_SetPriority(ADC_IRQn, NRF_APP_PRIORITY_LOW);
NVIC_EnableIRQ(ADC_IRQn);
}
/*void adc_init(void)
{
const nrf_adc_config_t nrf_adc_config = NRF_ADC_CONFIG_DEFAULT;
// Enable interrupt on ADC sample ready event
NRF_ADC->INTENSET = ADC_INTENSET_END_Msk;
sd_nvic_SetPriority(ADC_IRQn, NRF_APP_PRIORITY_LOW);
sd_nvic_EnableIRQ(ADC_IRQn);
}
*/
/**
* @brief Function for main application entry.
*/
int main(void)
{
adc_config();
//adc_init();
uart_config();
printf("\n\rADC HAL simple example\r\n");
printf("Current sample value:\r\n");
nrf_adc_start();
while (true)
{
// enter into sleep mode
__WFI(); //WAIT FOR INTERRUPT
//__SEV();
//__WFE();
//__WFE();
}
}
