How do I program the STM32F401CCU6?

Question

I am transitioning from Arduino to STM32 development. I just purchased an STM32F401CCU6 board and I cannot get it recognized by my computer. I am running Ubuntu 22.04. I have tried searching everywhere but there is such poor documentation and support for working with ST (compared to Arduino and Espressif). My board has a USB C port on it but after watching countless videos and reading numerous forums, I've come to know that normally we use external programmers for development with these STM boards. I also have an external programmer (FTDI) if that's how it is supposed to be done.

I have showed the output of my 'dmesg' window, clearly showing the device recognized on a hardware level. But it is not recognized anywhere else. I tried finding it as a COM port via Arduino but did not find any available ports. I tried programs like CoolTerm and Putty but I could not see the port appear there either. I tried 'ls /dev/tty*' but did not find the device anywhere.

[282059.230618] usb 3-1: new full-speed USB device number 51 using xhci_hcd
[282059.380114] usb 3-1: New USB device found, idVendor=0483, idProduct=df11, bcdDevice=22.00
[282059.380123] usb 3-1: New USB device strings: Mfr=1, Product=2, SerialNumber=3
[282059.380126] usb 3-1: Product: STM32  BOOTLOADER
[282059.380129] usb 3-1: Manufacturer: STMicroelectronics
[282059.380131] usb 3-1: SerialNumber: 359B33733237

I used the push buttons on the board to put it in DFU mode (no idea what that is) and I can confirm it worked because the user LED went off. But I still do not see it appear anywhere on my system. I also have a Nucleo F401RE and I never had to do anything extra to get it recognized by the same system (it was plug and play).

When I try to 'run' a program via CubeIDE, it says "No ST-LINK detected!". I have been stuck for days on this issue and I cannot figure out what needs to be done to flash a program onto it. It is just paperweight (a very inefficient one) at this point.

I tried using CubeProgrammer as well but could not establish a connection through either option - USB, UART nor ST-LINK. USB and UART require COM ports so they both failed. ST-LINK also failed to detect anything.

Any insights and guidance shall be greatly appreciated.

Answer 1

Looks like a WeAct BlackPill -- https://docs.zephyrproject.org/2.6.0/boards/arm/blackpill_f401ce/doc/index.html

It has a boot loader, as do all the stm ARM cortexes (I believe), but no on-board programmer. It does allow programming with a programmer, though -- you would need to pick up an ST-Link clone.

I think the page I reference above will give you enough direction to use your device.

"DFU" is Device Firmware Update -- i.e., programming the device using the bootloader.

UPDATE: It looks like there may be issues using the Cube environment to program via DFU (https://community.st.com/s/question/0D53W00000euMKeSAM/stm32cubeprogrammer-doesnt-support-dfu-files) I can't confirm.

https://youtu.be/b1123kz_3MM has instructions for using Cube to program these. It involves finding and installing the STM32 core for Arduino, and doing some stuff in the Arduino Board Manager.

Answer 2

There are issues with the 'Black Pill' (25MHz HS crystal) design and DFU. Recommendation from ST:

Note: Due to HSI deviation and since HSI is used to detect HSE value, the user must use low frequency rather than high frequency HSE crystal values (low frequency values are better detected due to larger error margin). For example, it is better to use 8 MHz instead of 25 MHz

Apparently you can physically heat the chip to shift HSI clock frequency and help it properly detect the HSE crystal frequency at power-up (it's looking to detect even MHz values), but why bother?

I suggest using an STlink (V2, V3, or clone, any of which just works). Debugging capability is really important anyway.

Answer 3

I figured out how to start 'using' the board. As Scott Seidman pointed out, it was indeed loaded with a custom bootloader from WeAct/Zephyr. Once I connected it via ST-Link using the SWD pins, I was able to connect it to CubeIDE and program it normally, like a Nucleo Board. I first had to perform an upgrade (which CubeIDE automatically prompts you to do) by putting the board in DFU mode. Depending on which board you have, it is a particular combination of the on-board buttons or switches.