Ok when I 1st hooked up the STM32unio over USB, windows detected it and said it installed "maple", or called it maple, and installed something and it seemed to be connected on COM5. So it must have some bootloader or something on it.
But I don't see anything I recognize in the device manager. My regular Arduino shows up as something, whose name I recognize easily...
I got it on amazon 2-3 years ago, and the item was sold by a store called Canaduino, but it's amazonpage is gone, so I can't read what others did with it. But it looks like a common BluePill
https://www.instructables.com/Programming-STM32-Blue-Pill-Via-USB/So from reading around, it might be a Maple mini clone, or just some common Blue Pill (but I'm new to all this crap and it's getting annoying).
So far, in Arduino's IDE, I've gone into boardmanger, and installed 2 or 3 things they list on this guide, like the using the github link for "package_stmicroelectronics_index.json", and installing the STM32 and STM8 stuff.
https://github.com/stm32duino/Arduino_Core_STM32/wiki/Getting-StartedAlso in windows10, I installed STM32CubeProgramer, but not to the default place. Then in Arduino 2.3.2 IDE, I'd select COM5 and a GENERIC STM32F1 series board, IDK if that's right.
Then when I would try to upload something, it would say it can't find some STM32 programmer_CLI. I probably had the wrong output mode too, like SWD. I tried serial too, but I'm connected over USB, maybe it doesn't work that way.
Now I read elsewhere I should install STMCubeProg in the default location. I had a hard time uninstalling the program. I tried this with the 2.16.0 version #, and still in the end I had to delete it all by hand.
https://community.st.com/t5/stm32cubeprogrammer-mcus/can-t-uninstall-stm32cube-programmer-v2-5-0-from-windows-10/td-p/191635I've rebooted the PC, reinstalled both Arduino IDE and STM32CubeProgrammer, to C:\Program Files.
But now when I hook up the BluePill/STM32uino, the USB makes the connect then disconnect sound. And I don't see it in device manger, under any name I can recognize.
So now what

?
I found a MP232EC chip, I think it's a TI MAX232. Can that be used for level shifting between a 3V3 STM32F103C8T6, and a 5V ATMEGA328 or ??
https://www.ti.com/lit/ds/symlink/max3232e.pdf?ts=1712907708973&ref_url=https%253A%252F%252Fwww.google.com%252FThere must be some way, to talk to this BluePill/chip, I have other logic chips, and 3V3 voltage regulators.