I'm trying to enter bootloader , Uart , with STM cubeprogrammer, using board is STM32F401 NUCLEO-64 . Help me ...

[Lkim.1]

Hi~

I'm trying to connect uart bootloader.

but there is something wrong. I can't connect bootloader via STM32CUBEPROGRAMMER

and I found the datasheet that STM32F401 NUCLEO-64 only support one uart for system memory.

1. I connect Uart1 (PA9, PA10)
2. I've already checked that Uart1 is working on user FW ( I have tested )
3. I connect BOOT0 and VDD ( I have checked 3.3V )
4. I checked BOOT1 is grounded.
5. I press the reset button.
6. I think STM32F401 NUCLEO-64 is on system memory boot. (cause I programmed blink led , when I press the reset button, it stopped)
7. I am trying to connect uart via STM cube programmer program.
8. but it shows error message that "Error: Activating device: KO. Please, verify the boot mode configuration and check the serial port configuration. Reset your device then try again... "
9. I used HSI clock which it presented on datasheet.
10. I checked that bootloader FW version , it is D1,

I don't know what's wrong with this.

any Ideas??

is that possible to using uart bootloader with STM32F401 NUCLEO-64?​

[Sebastiaan · Accepted solution]

Might make sense to scope the TX and RX to verify the "USART connection timing" (see AN2606).

Also, as you can see from the "Bootloader selection for stm32f401xyz" (multiple diagrams exist), the presence of a USB cable can (and will?) cause the device to switch to USB mode, in which case USART bootloader cannot be used.

[ABITT.1]

I use the NUCLEO STM32F746 and I must connect the UART1 on my PC, using RS232(3v3)/USB converter.

Be careful that the evaluation board dont have an RS232 driver (the RS232 voltage is 0/3v3 and not +12v/-12v)

[Lkim.1]

Thanks for your reply~

I accepted your advice!

I tried to know USART connection timing , using Oscilloscope.

connected probe to RX, TX and clicked connect button on the program.

then suddenly it works....

I don't understand why. but it works ~

and now it works fine , so far~

thanks again!

[Lkim.1]

thanks~

yeap~ I understand that uart1 is 0~3v3

anyway it works well now~

thank you for your comment~!

[smithderek2000]

I know this is old, but this just saved me - I had USB plugged in but was trying to use USART for bootloader and it wasn't working. Unplugged USB and it worked.