RTClock implementation for STM32F103

[abhaysbharadwaj]

Hello,
I had worked with the old core (Roger Clark) and I had used the <RTClock.h> library to get the systick time to understand the "System uptime" (basically number of seconds the microcontroller is running without a power cycle). This was helping me in determining a system's long time performance on whether it used to work continuously or if it was getting stuck and a power cycle was done to reset the microcontroller.

The same RTClock is not working for this core. Is a similar library available here? Or is there a way I can get the systick seconds in my code? Any help is appreciated.

[fpistm]

You can simply use millis()
https://www.arduino.cc/reference/en/language/functions/time/millis/

Or you can use the STM32RTC:
https://github.com/stm32duino/STM32RTC

[abhaysbharadwaj]

Hi,

millis() does not work since it gets reset to zero every time the microcontroller is reset using the "RESET" pin or "NVIC_System_Reset"

With RTClock, the count would get reset to 0 only with a power cycle (switch off - switch on) of the controller. Even putting the system to sleep and wake-up or using the NVIC_systemReset was not resetting the count.

RTC is being used for STANDBY mode (deep sleep functionality). I am not sure how I can use it for getting the "Device up-time".

[fpistm]

I don't see this kind of feature in the RTCLock.h.
Maybe You can use dwt for this:
https://github.com/stm32duino/Arduino_Core_STM32/blob/main/cores/arduino/stm32/dwt.h

[abhaysbharadwaj]

I think my explanation was not clear.
Adding an example to illustrate what I mean:

Test Code:

#include <RTClock.h> RTClock rt(RTCSEL_LSE); //internal RTC class int counter = 0; //store the device up-time count unsigned long deviceOperationTime = 0; void setup() { Serial.begin(115200); Serial.println("Device Powered ON"); } void loop() { ++counter; Serial.print("Count: "); Serial.print(counter); Serial.print("\t"); deviceOperationTime = rt.getTime(); Serial.print("Device Up-time: "); Serial.print(deviceOperationTime); Serial.println(" Seconds"); if (counter >= 5) { Serial.println("Max count reached. Triggering NVIC_SYS_RESET."); delay(100); nvic_sys_reset(); } delay(5000); } 

Image:

[fpistm]

you want something like a free running counter.
You can try something like this as a workaround

#include <STM32RTC.h> #include "stm32yyxx_ll_rcc.h" static int counter = 0; //store the device up-time count static unsigned long deviceOperationTime = 0; static unsigned long offsetOPTime = 0; STM32RTC& rtc = STM32RTC::getInstance(); void setup() { Serial.begin(115200); Serial.println("Device Powered ON"); rtc.begin(); rtc.attachSecondsInterrupt(rtc_SecondsCB); dwt_init(); enableBackupDomain(); if(LL_RCC_IsActiveFlag_SFTRST() || LL_RCC_IsActiveFlag_PINRST()) { offsetOPTime += getBackupRegister(LL_RTC_BKP_DR2); LL_RCC_ClearResetFlags(); } else { resetBackupDomain(); } } void loop() { ++counter; Serial.printf("Count: %i\t", counter); deviceOperationTime = (dwt_getCycles()/SystemCoreClock) + offsetOPTime; Serial.printf("Device Up-time: %i Seconds\n", deviceOperationTime); if (counter >= 5) { Serial.println("Max count reached. Triggering NVIC_SystemReset."); delay(100); setBackupRegister(LL_RTC_BKP_DR2, deviceOperationTime); NVIC_SystemReset(); } delay(5000); } /* callback function on each second interrupt */ void rtc_SecondsCB(void *data) { UNUSED(data); setBackupRegister(LL_RTC_BKP_DR2, (dwt_getCycles()/SystemCoreClock) + offsetOPTime); } 

[abhaysbharadwaj]

Will check this out! Thank you.

[fpistm]

Note that it is really a workaround.
It is planned to provide a new RTC feature to have a free running counter, anyway, maybe it will continue to run when reset occurs.