2024-01-12 08:12 AM - last edited on 2024-04-09 06:50 AM by Amel NASRI
Dear STMicroelectronics Support Team,
I hope this message finds you well. I am interested in identifying a microcontroller that meets certain specifications for my project. I would appreciate your assistance in identifying the most suitable MCU.
MCU Requirements:
If you could provide information about any MCU that meets these requirements or suggest where I can find such information on your website, I would be very grateful.
Thank you very much for your time and assistance.
Sincerely,
Solved! Go to Solution.
2024-01-12 10:27 AM
STM32CubeMX has a part selection that can be helpful here.
You're probably out of luck here with the VBAT pin requirement. All chips have RTC/I2C.
No SO-8 chips have a VBAT pin. The STM32G0 series has that pin, but only in the LQFP48 packet. My guess is other series are similar.
2024-01-12 08:28 AM
Most of the STM32 parts have these features. Some of the L Series lack the VBAT as they are expected to be battery powered, and just go into STANDBY using minimal power and running their RTC
What does you code foot-print and RAM usage look like? What MCU do you need? Clocking at what speeds?
The physically smaller parts have smaller die, and less FLASH and RAM. The QFN-28 and QFN-20 packages can be pretty small and still manageable
Perhaps find a local sales rep or distributor. An FAE might be able to help unpack you actual requirements and use case.
2024-01-12 10:22 AM
I am creating a light-based alarm clock that simply turns on an RGB LED according to the wake-up time.
The code is very simple:
I'm not brave enough to solder the QFN yet.
2024-01-12 10:27 AM
STM32CubeMX has a part selection that can be helpful here.
You're probably out of luck here with the VBAT pin requirement. All chips have RTC/I2C.
No SO-8 chips have a VBAT pin. The STM32G0 series has that pin, but only in the LQFP48 packet. My guess is other series are similar.
2024-01-12 01:38 PM
Thank you,
It's a pity that the VBAT is not implemented in all chips that integrate RTC.
Very kind, thank you very much.
2024-01-12 02:08 PM
Probably more people want a GPIO pin than VBAT. That would have taken the IO count from 6 down to 5.
Soldering an LQFP is doable. Not as easy as SO-8 but it can be done with hobby-quality tools if you have some patience, flux, and a solder wick.
2024-01-12 04:00 PM - edited 2024-01-12 04:06 PM
Hello and thank you, I found this:
You have many pins that will be unused, but it's the smallest one I found with VBAT.
Thanks again and greetings.
2024-01-12 04:03 PM
The STM32G030K6T6 (LQFP32) does not have a separate VBAT pin. Only LQFP48 chips from that series have one.
2024-01-12 04:12 PM
Yes, I realized after posting, it's already corrected.
Thank you very much anyway, you are very kind.
2024-01-12 04:13 PM
Currently, I am using this one, but it costs 5€, and the STM32, besides saving me the external RTC, doesn't even reach 1€, and that is magnificent!!