Arduino for STM32

Hi,

I purchased the early release of maple mini which is the BAITE version, then I thought I broke it because I couldn't program it with the USB but didn't throw it. And bought couple of the recent maple clones. One is working and appearing on COM port but can't connect it to the Arduino serial monitor. And the other one is like the first one as it can't be programmed with the USB and not appearing on the COM port.

After I bought the ST LINK V2, I was able program all the boards with SWD.

Now my question, is what is the reason the USB programming/communication in maple mini boards get broken ?

I'm still happy the boards aren't completely broken and I can program them and if I want to display any information, I can use any LCD for that task.

for maple mini stm32f103 you need either the st-link or a usb-uart dongle to program it (set boot0 and press reset)
https://sites.google.com/view/makeriot2 ... rduino-ide

Or better get a stm32f401/f411 black pill board , hold the boot0 button and toggle reset. That would drop into the DFU programming mode.
And you can program it over usb.

it is possible to install a custom bootloader on it (e.g. stm32f103 maple mini or blue pill) with the st-link or usb-uart dongle. But that is not a standard feature in stm32f103

Thank you so much man !

Let me get through the solutions you mentioned.

But why it doesn't work with USB anymore ? is there a way to fix this problem and get the maple mini to work over the USB again ?

And you're right I won't buy maple mini again, I would like to buy the STM32F4 new boards on Aliexpress, I've put this on in my cart:
https://www.aliexpress.com/item/1005003 ... fqvMT&mp=1

It's no longer available but I'm searching for a similar one.

This one is good, they also describe in the product page to program it with different methods.

https://www.aliexpress.com/item/1005004 ... oaV5ssG8zc

if you have the st-link, you can try to install this bootloader on your stm32f103 maple mini
https://github.com/rogerclarkmelbourne/ ... bootloader
these days it is 'unsupported' but that it still works. this is roger's much improved 'maple bootloader'
this is the 'history' for where 'stm32duino' started
https://www.leaflabs.com/maple
hence roger's core is also known as 'maple core', it still works (well) but is 'unsupported' on stm32f103.
the boot loader likely works in the 'official' core as well.
The difference is, your code will be offset from the normal start of flash 0x8000000 to 0x8002000 as the bootloader sits in front.
When you build the sketch, you'd need to specifically select that boot loader as well.
it is a DFU (usb device firmware update) bootloader as it is originally designed.

stm32f401/f411 and f4xx has a DFU bootloader built-in i.e. it is in 'system storage', so you have all your flash storage from 0x8000000 - start of flash
all it takes to toggle this boot loader is
- press both boot0 and reset
- hold boot0, but release reset
- release boot0 1s later
now it is in DFU mode and you can load your .bin file at 0x8000000 - stm32f401/f411, f4xx - many other series as well, check in ST web for the reference manuals.
https://www.st.com/resource/en/applicat ... ronics.pdf

stm32f401 is a *much* faster chip vs stm32f103 for the same Mhz.
because stm32f4xx has that 'ART accelerator' on chip cache + FPU.
that 'ART accelerator' alone can change reading from flash say from 5 wait states to 0 wait states (if the code or data is in cache).
and if the number of wait states is higher say 10 wait states, and say from 10 wait states to 0 wait states, it'd be like 10x faster (if the code or data is in cache).
+ the FPU, you can try *single precision* floating point calc, the speeds is probably fast enough to process audio from ADC on the fly as a DSP.

Hi,

I wanted to say thank you for this wonderful answer.

What happened is that, the maple mini boards stopped programming through the USB and I only can program it with the ST-LINK V2.

r1s8k wrote: ↑Fri Jan 13, 2023 3:38 am What happened is that, the maple mini boards stopped programming through the USB and I only can program it with the ST-LINK V2.

As ag123 mentioned, you need to flash usb bootloader to be able to flash using USB.
If you use ST-Link or Serial adapter to flash board, you will overwrite bootloader and won't be able to use USB to flash boards until you flash usb bootloader again.