STM32F103RDT6 Serial Upload

[hyur]

hello expert

I'm currently using a STM32F103RDT6 and I'm developing it via Arduino IDE.

Among the upload methods of Arduino IDE, I am uploading firmware through ST-LINK, but it is cumbersome to continuously use ST-LINK due to the structure of the hardware I am making. And modifying this hardware is difficult.
So I want to upload firmware by Serial Method.
Serial communication uses USART3 connected by FTDI.

Can I upload serially via USART3?
I can't go any further as I don't have any expertise in this area.

If there is a way to upload it serial, even a small tip would be fine, please advise.

[fpiSTM]

You can refer to this:
https://www.st.com/resource/en/applicat ... ronics.pdf

It seems only USART1 allows Serial upload.

[hyur]

@fpiSTM

Thank you for answer.

So, is there any way to use USART3 pins (PC10,11) as USART1?
Please tell me everything except how to jump on the circuit.

[fpiSTM]

Well, if you want use USART3 then you will have to implement your own bootloader.

[hyur]

@fpiSTM

I understand what you mean

Thank you very much for your reply. It was a big help.

[hyur]

@fpiSTM

Following your advice, I tried to build a new bootloader.

I tried to assign functions to pins by selecting STM32F103RDT6 through STM32CudeMX, but I could only select USART3 for PC10 and 11 pins.
(I want to give USART1 function to PC10,11.)

Is it different from the way you advised?

[GonzoG]

You cannot assign any pin to any interface. PC10 and PC11 can be assigned only to UART4 or USART3.
Here's STM32F103RD datasheet:
https://www.st.com/resource/en/datashee ... f103rd.pdf