Forgot to add SWCLK and SWDIO to pin layout on STM32

[D4no0]

Hello,
So I wanted to start developing on STM32.
I am using STM32CubeIDE that uses STM32CubeMX as layout by default.
The development board is a generic blue pill STM32F103C8T6.
The problem appeared when I tried to make a blink sketch and upload it to the device using ST-LINK V2. It uploaded, however after that I was unable to upload anymore. Later I found out that you need to specifically set the SWCLK and SWDIO in MX. My BOOT0 mode is still working so I tried to upload STMduino to it, however from what I've read this dev board has an wrong value resistor that needs to be replaced (I don't really want to solder a smd resistor with soldering iron), so I'm stuck here. I wanted to know if there is a way to flash a new firmware?

[capt bullshot]

Hello,
So I wanted to start developing on STM32.
I am using STM32CubeIDE that uses STM32CubeMX as layout by default.
The development board is a generic blue pill STM32F103C8T6.
The problem appeared when I tried to make a blink sketch and upload it to the device using ST-LINK V2. It uploaded, however after that I was unable to upload anymore. Later I found out that you need to specifically set the SWCLK and SWDIO in MX. My BOOT0 mode is still working so I tried to upload STMduino to it, however from what I've read this dev board has an wrong value resistor that needs to be replaced (I don't really want to solder a smd resistor with soldering iron), so I'm stuck here. I wanted to know if there is a way to flash a new firmware?

Connect the STM32 reset input to the ST-Link reset output, and use "connect under reset" with the ST-Link tool.

[ogden]

Connect the STM32 reset input to the ST-Link reset output, and use "connect under reset" with the ST-Link tool.

Right. Other way around:

1. Press & hold reset button on the pill.
2. Start programming (it will seemingly hung while reset pushed).
3. Release reset button (programming supposedly will commence).

[D4no0]

I suppose you are using the ST-Link utility from windows? I am currently on linux with a limited version of this tool and it shows an error when I release the reset button.

[capt bullshot]

Usually I'm using linux and openocd with an ST-Link, and have the reset line connected to the target.
Using openocd and ST-Link, the "hold the reset button" works for me, if you release the button at the right moment.

But as you've pointed out, I've mentioned the windows ST-Link utility and it's "connect under reset" setting as the last resort.
Never tried the Linux version of that utility, but afaik it provides the same functionality.

[ogden]

I suppose you are using the ST-Link utility from windows? I am currently on linux with a limited version of this tool and it shows an error when I release the reset button.

Try minimizing delay between program start and reset release. Do it close to "same time". Also check timeout settings for debug hardware, increase if needed

[DDunfield]

As others have said, "Connect under reset" works for cases where you've used the debug pins for other purposes.

The "wrong value resistor" on the Blue-Pill is for the USB port, and it may work "as is" with some systems, however the point is a bit moot because IIRC the STM32F103C8T bootloader doesn't support USB.

Do you have a USB serial adapter providing RxD, TxD at 3v levels?  If so, you can use that to access the on-board bootloader and it works fine on the Blue-Pill (done it many times!).  If you don't already have such an adapter you probably want one, because using an on-chip USART is the simplest way to implement a debug console (very little code to talk to it).

Dave

[DDunfield]

Another thing you could try:

Set the Boot0/Boot1 pins to activate the on-chip bootloader out of reset.
This should prevent your code from running and re-configuring the debug pins.

Then try programming with SWD

Don't forget to re-configure boot to flash afterward.

Dave