Change rtc clock source (in sdkconfig.h)

2ni · May 6, 2019, 6:01pm

Hi
I’d like to change the rtc clock source for arduino-esp32 from internal to:
CONFIG_ESP32_RTC_CLOCK_SOURCE_EXTERNAL_CRYSTAL

I tried updating sdkconfig.h, but when compiling my project I now get a lot of:
#define CONFIG_ESP32_RTC_CLOCK_SOURCE_EXTERNAL_CRYSTAL 1
^
:0:0: note: this is the location of the previous definition

What is wrong?

pfeerick · May 7, 2019, 5:25am

From this issue, since you say it’s the arduino-esp32 you’re trying to change this on, it looks like it’s a bit of an involved process… where you need to rebuild libesp32.a with the right flags set, and then add some extra lines to your code to actually use it…

github.com/espressif/arduino-esp32

Switch RTC clock to external 32kz xtal

opened 11:35AM - 16 Mar 18 UTC

closed 05:23PM - 25 Mar 18 UTC

errolt

### Hardware: Board: ESP-WROVER-KIT Core Installation/update date: 2018…-03-10 IDE name: Arduino IDE Flash Frequency: 40Mhz Upload Speed: 921600 ### Description: Is there any way, or plans for a way, to enable the slow xtal osc for the RTC? The current way the RTC is set up seems to keep time during deep sleep, but drift seems extreme at times. I have tried to change the RTC clock using: rtc_clk_32k_bootstrap(); rtc_clk_32k_enable(true); rtc_clk_slow_freq_set(RTC_SLOW_FREQ_32K_XTAL); But that did not enable the osc, and it prevents deepsleep from ever waking up. ### Sketch: ```cpp #include <WiFi.h> #include "time.h" #include <rom/rtc.h> const char* ssid = "abc"; const char* password = "xyz"; const char* ntpServer = "pool.ntp.org"; const long gmtOffset_sec = 3600; const int daylightOffset_sec = 3600; void printLocalTime() { struct tm timeinfo; if(!getLocalTime(&timeinfo)){ Serial.println("Failed to obtain time"); return; } Serial.println(&timeinfo, "%A, %B %d %Y %H:%M:%S"); } void setup() { Serial.begin(115200); //init and get the time if(rtc_get_reset_reason(0)!=DEEPSLEEP_RESET) { //connect to WiFi Serial.printf("Connecting to %s ", ssid); WiFi.begin(ssid, password); while (WiFi.status() != WL_CONNECTED) { delay(500); Serial.print("."); } Serial.println(" CONNECTED"); Serial.println("Getting Time."); configTime(gmtOffset_sec, daylightOffset_sec, ntpServer); printLocalTime(); //disconnect WiFi as it's no longer needed WiFi.disconnect(true); WiFi.mode(WIFI_OFF); } configTime(gmtOffset_sec, daylightOffset_sec, ntpServer); printLocalTime(); esp_sleep_pd_config(ESP_PD_DOMAIN_RTC_PERIPH, ESP_PD_OPTION_ON); Serial.println("Going to sleep"); esp_sleep_enable_timer_wakeup(5000000); esp_deep_sleep_start(); } void loop() { } ```

Maybe @maxgerhardt knows something about this?

maribeiro · March 22, 2020, 5:33pm

I know this is an old thread, but it’s exactly what I need to do and couldn’t find info anywhere.
I have an ESP32 project using framework = arduino and need to change CONFIG_SECURE_SIGNED_APPS_NO_SECURE_BOOT at sdkconfig.h.
How can I change it ?

maribeiro · March 24, 2020, 3:34pm

@ivankravets can you explain how to do it pls?