The main loop in our nRF9160 (NCS v1.8.0) is a typical main loop with semaphore following https://docs.zephyrproject.org/latest/kernel/services/threads/system_threads.html?highlight=writing main function#id2
static K_SEM_DEFINE(timer_semaphore, 0, 1); static void rtc0_handler(nrfx_rtc_int_type_t int_type) { // [ some logic related to RTC count ] if(expired) { LOG_INF("Give timer semaphore"); k_sem_give(&timer_semaphore); } } static int rtc_config(void) { int32_t err_code = 0; nrfx_rtc_config_t config = NRFX_RTC_DEFAULT_CONFIG; config.prescaler = 4095; err_code = nrfx_rtc_init(&rtc0, &config, rtc0_handler); // [ some error logic ] nrfx_rtc_tick_enable(&rtc0, true); nrfx_rtc_enable(&rtc0); return 0; } void main(void) { // [ some initializations ] rtc_config(); // [ other initializations ] while (1) { LOG_INF("Wait for timer semaphore"); k_sem_take(&timer_semaphore, K_FOREVER); LOG_INF("A timer expired"); // [ sensor data collect and send ] } }
But there is a huge delay between the time semaphore is given and taken.
Some typical log extract follows:
00> [00:12:54.485,198] <inf> : Wait for timer semaphore
00> [00:15:40.744,873] <inf> : Give timer semaphore
00> [00:17:04.000,000] <inf> : A timer expired
-> 84 seconds delay
00> [00:17:06.688,018] <inf> : Wait for timer semaphore
00> [00:18:40.744,873] <inf> : Give timer semaphore
00> [00:21:23.187,957] <inf> : A timer expired
-> 83 seconds delay
00> [00:21:26.028,198] <inf> : Wait for timer semaphore
00> [00:24:40.744,873] <inf> : Give timer semaphore
00> [00:25:36.000,000] <inf> : A timer expired
-> 56 seconds delay
How is it possible to troubleshoot this kind of issue?
