Flashing Bootloader for BluePill Boards
These boards are low cost and very well supported by STM32 Arduino
Officially Supported now at STM32duino
One needs to flash the Bootloader to make this board work with modified MAPLE booloader.
For that here are the Steps:
Here is a link to all the binary files available in precompiled form.
The specific file needs to be selected.
If you have the above board most linkly the LED is on PIN PC13 then the file to use is generic_boot20_pc13.bin
Note this file also needs a USB Disconnect pin connected to Pin PB9
Figure shows the modification needed for the R10 resistance that comes populated on the board.
One needs to replace this to a 1.5k resistance.
The Board would still need reset button press some times in case the USB Serial is not getting detected.
In case you can't affort the fancy circuit shown above, then use a Pull up of 1.5k on Pin PA12
This is the USB D+ line of the MCU.
Here is a picture showing the MOD
Though this would work, but the USB reset some times fails with this MOD.
One needs to disconnect the board from USB and then reconnect to recover some times.
Figure shows the circuit needed for USB Connection to STM32F103C8T boards:
First connect the board using the ST-LINK programmer.
Copy the firmware file generic_boot20_pc13.bin or what ever in your case to :
(Arduino)\hardware\Arduino_STM32-master\tools\win - Windows
In case of windows this would correct in case of linux use the specific directory.
(Arduino)\hardware\Arduino_STM32-master\tools\linux64 - Linux 64-bit
(Arduino)\hardware\Arduino_STM32-master\tools\linux - Linux 32-bit
Here the (Arduino) is the default folder where the Arduino Sketches are stored.
In case of Windows we run the command:
stlink\ST-LINK_CLI.exe -c SWD -P generic_boot20_pc13.bin 0x8000000 -Rst -Run
To Flash the board. Here generic_boot20_pc13.bin needs to be replaced by the respective bin file selected earlier.
./stlink/st-flash write generic_boot20_pc13.bin 0x8000000
./upload-reset
To Flash the board. Here generic_boot20_pc13.bin needs to be replaced by the respective bin file selected earlier.
The last command would reset the board to begin execution.
Note: The new write keyword in the latest version of texane/stlink.
https://github.com/rogerclarkmelbourne/Arduino_STM32/wiki/stm32duino-bootloader
https://github.com/rogerclarkmelbourne/STM32duino-bootloader
https://github.com/rogerclarkmelbourne/Arduino_STM32/wiki/Bootloader