2023-07-31 06:44 AM - edited 2023-08-06 11:30 PM
I would like to program an STM32F446RET MCU with USB DFU bootloader. I did the following connections:
- board VCC to USB cable and VBUS_FS
- board GND to USB cable
- UDB_DP to USB cable
- USB_DN to USB cable
When reset BOOT0=3.3V and BOOT1=GND
The MCU seems to enter in the bootloader (the main program does not start) but STM32Programmer is not able to connect to the USB device
Am I missing something?
EDIT 1: This is a circuit that is very close to the one I used
EDIT 2
I discovered the source of the problem, but not the solution. Here's more details. There is a USB A receptacle on the board and:
It seems like that when USB C is used we need an additional circuit (the same that it is inside the cable adapter). Which circuit? I'm not able to find anything on the internet
2023-07-31 07:03 AM
Is this a custom board? If so, is a schematic available?
Can you program it using the SWD connections?
> board VCC to USB cable and VBUS_FS
I'm hoping you're converting the 5V to 3.3V with an LDO before connecting it to board VCC, right?
2023-07-31 07:30 AM - edited 2023-08-01 12:22 AM
Thanks for the help!
Yes, this is a custom board. And I am able to program it with SWD.
I edited the question to add a simplified schematic of the whole circuit.
The board is not powered through USB but has another power source which provide both 5V (which is connected to USB and VBUS_FS) and 3.3 V (to power the MCU).
2023-07-31 07:32 AM
The reply is below, sorry for the confusion. I'm new to the STM forum