I’m developing a new board which requires a custom built STM32G431 MCU, and accidentally overclocked it to 255MHz. The G431 is rated at 170MHz. SimpleFOC worked, but the peripherals were messed up. I was able to get the UART working, and didn’t try anything else. I don’t know if this information has really any value, but just FYI, it’s possible to overclock if you are careful. The difference between 170 and 255 is quite a lot, 85MHz is more extra performance that another BluePill.
The overclocked MCU was tested on a closed loop with 3 hall sensors in voltage and velocity mode. I did not try current sensing.
Design wize this is important since the MCU draws power and heats up in accordance with the processing power, so one should take it into account. We’ll just like overclocking a PC (CPU).
Take the STSpin32G4. You don’t want to power anything external with its inbuilt LDO while running a OC setup.
And you’ll be running outside the Spec. but if it is stable…
I didn’t notice overheating. The MCU package I got has bottom ground heat sink, so that may have helped a lot.
I didn’t realize it’s overclocked (I apparently made a mistake with the clock config) and accidentally found out when I tested, so it was running OK for a while. However, I would not put this into production. This is more of a curiosity fact. I didn’t even know you can overclock the STM MCUs. I mean, I know you can set the clock parameters outside but I always thought the MCU silicon will fail the clock and default to an internal setup. Apparently not.
From what I gather from the STSpin32G4 datasheet there is a 120mA limit on the integrated LDO. It’s also possible to supply it from an external source, but I should think there is some headroom for OC if not used for other stuff and maybe supply the Analog Domain from an external LDO.
Does the MCU you OC’d have an internal LDO?
Interesting stuff, for sure. Although maybe some fiddling with SPI timings and other libraries are needed, like you say this is uncharted
It’s a generic MCU, no LDO.