STM32RTC with Arduino Portenta H7 based on ArduinoCore-mbed

[hideakitai]

Hi, thanks for the great work! I forked the STM32RTC library because I'd like to make it work with Arduino Portenta H7 (STM32H747XIH6) based on ArduinoCore-mbed.

https://github.com/hideakitai/STM32RTCMbed

I built it using ArduinoCore-mbed and got most of the basic RTC functionality examples working.

hideakitai/STM32RTCMbed#1

However, only the Alarm functionality is not working. It looks like RTC_Alarm_IRQHandler() is not being called. So, let me ask two questions:

1. If you use this library with Arduino Portenta H7 (STM32H747XIH6) based on Arduino_Core_STM32, can you get the Alarm to work successfully? (Sorry, I don't have ST-Link, so I haven't confirmed if it works with Arduino_Core_STM32 and STM32RTC...)

2. If no.1 works fine, do you have any idea what the cause might be, based on your abundant and deep experience with STM32 HAL/LL? Any information or advice would be greatly appreciated (I'm not very familiar with STM32 HAL/LL. The code looks good to me, but perhaps my code or something in ArduinoCore-mbed or mbed-os has some problems).

I will briefly explain what I did in the above pull request to get STM32RTC to work with ArduinoCore-mbed.

• b3506cd First, I imported codes from Arduino_Core_STM32, which were included from STM32RTC but did not exist in ArduinoCore-mbed.
• 4146b46 Secondly, no macro is defined to determine the series, such as STM32H7xx, so I defined one.
• d6d09e5 I renamed voidFuncPtr to avoid conflict with the ArduinoCore-mbed definition.
• ed28495 Changed SysTick_Handler() to WEAK since it seems to be already implemented in mbed-os (libmbed.a) and causes a "multiple definitions" linker error.

That's all. As mentioned above, the basic RTC example works fine. Only the Alarm Interrupt is not working.

I would greatly appreciate your experience and knowledge. Thank you very much for your valuable time.

[fpistm]

Hi @hideakitai

• If you use this library with Arduino Portenta H7 (STM32H747XIH6) based on Arduino_Core_STM32, can you get the Alarm to work successfully? (Sorry, I don't have ST-Link, so I haven't confirmed if it works with Arduino_Core_STM32 and STM32RTC...)

Never tested as the core doesn't support the Arduino Portenta board.

About the second point, I guess the libmed.a already implement the RTC_Alarm_IRQHandler(). So your one is simply not called.

[hideakitai]

Hmm... not working. I will explore more!

[hideakitai]

In my next experiment with STM32LowPowerMbed (STM32LowPower for ArduionoCore-mbed), the RTC alarm seems to be enabled because STM32LowPower::setAlarmTime(ms) works correctly.

https://github.com/hideakitai/STM32LowPowerMbed/blob/b05838f9309089dfc5b5bbb40173ec0f82f11dc2/src/STM32LowPowerMbed.cpp#L231

In this function, the RTC alarm is set and enabled like:

https://github.com/hideakitai/STM32LowPowerMbed/blob/b05838f9309089dfc5b5bbb40173ec0f82f11dc2/src/STM32LowPowerMbed.cpp#L318-L320

So only the RTC alarm IRQ handler is not working, maybe...

[hideakitai]

I was mistaken. It seems that the examples related to RTC Alarm is not working after all...

[fpistm]

Well hard to help on this. You should probably ask on Arduino forum or ArduinoCore-mbed GitHub.
You could also try to debug and see if the Alarm is properly configured and if the ALARMA IT is raised.

[hideakitai]

Thanks for your support! I will debug while familiarizing myself with how to handle HAL. If you notice any STM32H7-specific settings, please let me know. (I think it is probably due to the override of HAL functions on the ArduinoCore-mbed or mbed-os side)