Hi there, I have done search and know there are several similar questions, but unfortunately I didn't find any useful answer after carefully reading through them, thus I decide to post a new question, and wish it could help others in the future.
As suggested by the answers under the similar questions, I have called app_timer_start(), and the timer is of APP_TIMER_MODE_REPEATED.
I did debug, and traced to the function rtc1_counter_get(), but the NRF_RTC1->COUNTER is ZERO.
Could anyone give me any hints?
The background is I am studying the example in this timer tutorial, and want to obtain the elapsed time between two events with function app_timer_cnt_diff_compute
The main() function is as follows,
int main(void)
{
SEGGER_RTT_ConfigUpBuffer(0,NULL,NULL,0,SEGGER_RTT_MODE_BLOCK_IF_FIFO_FULL);
// Request LF clock.
lfclk_request();
// Initialize the application timer module.
APP_TIMER_INIT(APP_TIMER_PRESCALER, APP_TIMER_OP_QUEUE_SIZE, false);
// Configure GPIO's.
gpio_config();
// Create application timers.
create_timers();
SEGGER_RTT_WriteString(0, "SEGGER Real-Time-Terminal: \r\n\r\n");
// Main loop.
while (true)
{
// Wait for interrupt.
__WFI(); // take care, may change!
}
}
The relevant code is as follows, where gpio_config() calls nrf_drv_gpiote_in_init, which further calls function gpiote_event_handler.
static void gpio_config()
{
.......
// Configure input pins for buttons, with separate event handlers for each button.
err_code = nrf_drv_gpiote_in_init(BUTTON_1_PIN, &in_config, gpiote_event_handler);
APP_ERROR_CHECK(err_code);
.......
}
//Button event handler.
void gpiote_event_handler(nrf_drv_gpiote_pin_t pin, nrf_gpiote_polarity_t action)
{
uint32_t watchdog_timer;
uint32_t app_timer_cur;
uint32_t app_timer_diff;
uint32_t err_code;
static uint32_t timeout = 0;
switch (pin)
{
case BUTTON_1_PIN:
err_code = app_timer_start(m_led_a_timer_id, APP_TIMER_TICKS(200, APP_TIMER_PRESCALER), NULL);
APP_ERROR_CHECK(err_code);
/* Set watchdog timer */
app_timer_cnt_get(&watchdog_timer);
break;
case BUTTON_2_PIN:
err_code = app_timer_stop(m_led_a_timer_id);
APP_ERROR_CHECK(err_code);
/* Check for a watchdog timeout */
app_timer_cnt_get(&app_timer_cur);
app_timer_cnt_diff_compute(app_timer_cur, watchdog_timer, &app_timer_diff);
SEGGER_RTT_printf(0, "app_timer_diff is: %u \r\n", app_timer_diff);
break;
case BUTTON_3_PIN:
// Start single shot timer. Increase the timeout with 1 second every time.
timeout += 1000;
err_code = app_timer_start(m_led_b_timer_id, APP_TIMER_TICKS(timeout, APP_TIMER_PRESCALER), NULL);
APP_ERROR_CHECK(err_code);
break;
case BUTTON_4_PIN:
nrf_drv_gpiote_out_set(LED_2_PIN);
break;
default:
break;
}
}
Many thanks!
