BluePill using Roger USB download process

maxgerhardt · March 4, 2020, 6:03pm

Seems like a usage error. Your sketch may be written for the STM32Duino core (called “stm32” in PIO) and not the maple core by Roger Clark. The maple board uses core: "maple" while bluepill_f103c8 defaults to stm32:

The SPI class in the Maple core is instantiated by using only the SPI number from 1 to 3. The slave select / NSS pin is then given in the beginTransaction() call.

github.com

rogerclarkmelbourne/Arduino_STM32/blob/0383384f4cc91aadee1501e11bf08dd3e62d9fb9/STM32F1/libraries/SPI/src/SPI.cpp#L112-L115


      
          SPIClass::SPIClass(uint32 spi_num)
          {
              _currentSetting=&_settings[spi_num-1];// SPI channels are called 1 2 and 3 but the array is zero indexed

The STM32Duino core fits the code you have shown with the 4 pins in the consturctor.

github.com

stm32duino/Arduino_Core_STM32/blob/main/libraries/SPI/src/SPI.cpp#L46


      
            *         or ST format (Pxy).
            * @param  ssel: SPI ssel pin (optional). Accepted format: number or
            *         Arduino format (Dx) or ST format (Pxy). By default is set to NC.
            *         This pin must correspond to a hardware CS pin which can be managed
            *         by the SPI peripheral itself. See the datasheet of the microcontroller
            *         or look at PinMap_SPI_SSEL[] inside the file PeripheralPins.c
            *         corresponding to the board. If you configure this pin you can't use
            *         another CS pin and don't pass a CS pin as parameter to any functions
            *         of the class.
            */
          SPIClass::SPIClass(uint32_t mosi, uint32_t miso, uint32_t sclk, uint32_t ssel)
          {
            _spi.pin_miso = digitalPinToPinName(miso);
            _spi.pin_mosi = digitalPinToPinName(mosi);
            _spi.pin_sclk = digitalPinToPinName(sclk);
            _spi.pin_ssel = digitalPinToPinName(ssel);
          }
          
          /**
            * @brief  Initialize the SPI instance.
            */

So it’s very clear that your sketch was written against STM32Duino/STM32 core and not maple, so using board = bluepill_f103c8 is correct for that. Now to the question

The STM32Duino doesn’t activate the USB CDC interface by default. See Difficulty with getting USB serial [USB CDC] working - #6 by maxgerhardt for the needed flags.

I don’t however know if it’s possible to have the USB DFU bootloader from the Maple core AND the USB CDC from the STM32Duino core running… You might still try to pre-flash the Maple bootlader, add upload_protocol = dfu to the platformio.ini and then upload a STM32Duino firmware.