RTC_CLK_SRC_INT_8MD256 Causes Deep Sleep Wake-Up

[hyunwook.lee]

I'm using the ESP32-PICO-MINI-02 module in a system that repeatedly cycles between deep sleep and wake-up every 30 minutes. Initially, I used the default RTC clock source in IDF menuconfig, RTC_CLK_SRC_INT_RC, but I found that the time accuracy was very poor. Therefore, I decided to switch to RTC_CLK_SRC_INT_8MD256.

Component config -> Hardware Settings -> RTC Clock Config -> RTC clock source
RTC_CLK_SRC_INT_RC: Internal 150 kHz RC oscillator
RTC_CLK_SRC_INT_8MD256: Internal 8.5MHz oscillator, divided by 256 (~33kHz)

However, after changing the RTC clock source to RTC_CLK_SRC_INT_8MD256, I encountered an issue: after a soft reset (via the esp_restart function), the system fails to wake up from deep sleep. When I revert back to using RTC_CLK_SRC_INT_RC, the system wakes up normally.

I would like to use RTC_CLK_SRC_INT_8MD256 and have the system wake up correctly. Any help would be greatly appreciated.


Attached is my slip entry code below.

Code: [Select all] [Expand/Collapse]

1. void sleep_enter_deepsleep(uint32_t sleep_time, sleep_wakeup_source_e wakeup_source)
2. {
3.     isolate_rtc_gpio();
4.  
5.     struct timeval now;
6.     gettimeofday(&now, NULL);
7.  
8.     if (sleep_time > 0) {
9.         _target_wakeup_time.tv_sec = now.tv_sec + sleep_time;
10.  
11.     } else if (_target_wakeup_time.tv_sec < now.tv_sec) {
12.         _target_wakeup_time.tv_sec = now.tv_sec + env_config_get__wakeup_intreval();
13.     }
14.  
15.     int new_sleep_time = _target_wakeup_time.tv_sec - now.tv_sec - EARLY_WAKEUP_SEC;
16.  
17.     // minimum sleep time is 10 sec
18.     new_sleep_time = (new_sleep_time < 10) ? 10 : new_sleep_time;
19.  
20.     if (wakeup_source == SLEEP_WAKEUP_TIMER || wakeup_source == SLEEP_WAKEUP_BOTH) {
21.         // setup sleep time
22.         esp_sleep_enable_timer_wakeup(new_sleep_time * 1000000LL); // esp_err_t -> ESP_ERR_INVALID_ARG
23.         ESP_LOGI(TAG, "Entering DeepSleep, Timer: %ds", new_sleep_time);
24.     }
25.  
26.     if (wakeup_source == SLEEP_WAKEUP_BUTTON || wakeup_source == SLEEP_WAKEUP_BOTH) {
27.         // set wakeup source
28.         rtc_gpio_pullup_en(GPIO_SW_INIT_B);
29.  
30.         gpio_set_direction(GPIO_SW_INIT_B, GPIO_MODE_INPUT);
31.  
32.         int gpio34_level = gpio_get_level(GPIO_SW_INIT_B);
33.         ESP_LOGI(TAG, "GPIO 34 level before sleep: %d", gpio34_level);
34.  
35.         if (gpio34_level == 0)
36.             ESP_LOGW(TAG, "GPIO 34 was LOW, err");
37.  
38.         // set wakeup source -> SW_INT_B (GPIO 34)
39.         esp_sleep_enable_ext0_wakeup(GPIO_SW_INIT_B, 0); // trigger on falling edge
40.     }
41.  
42.     gettimeofday(&_sleep_enter_time, NULL);
43.     s_count++;
44.     esp_deep_sleep_start();
45. }

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