STM32F103C8 64/128k devices missing third serial port.

[AndKe]

I see option for Serial and Serial1 , yet a BluePill should have three USARTs - what is going on here ?
I wish there were a spreadsheed/table that shows supported features of different ST's ?

[stas2z]

Create build_opt.h file in yr sketch dir with following content
-DENABLE_HWSERIAL2 -DENABLE_HWSERIAL3

[fpistm]

Hi @AndKe
All U(S)ART from a STM32 are managed.
By default Arduino instantiate one named Serial which is mapped to the one defined in the variant:

Arduino_Core_STM32/variants/PILL_F103XX/variant.h

Line 111 in 2b723f8

#define SERIAL_UART_INSTANCE 1

For BP USART1 is used, so Serial1 is instantiate and mapped to Serial. If you enable USB CDC to superseded Serial and kept Serial enabled then Serial1 is always instantiate and SerialUSB is mapped on Serial

If you need more HW Serial then see:
https://github.com/stm32duino/wiki/wiki/API#hardwareserial

[AndKe]

Thank you.

[AndKe]

I created build_opt.h with the single line -DENABLE_HWSERIAL2 -DENABLE_HWSERIAL3

very simple test code contain

  Serial.begin(9600);
  Serial2.begin(9600);
  Serial3.begin(9600);

but I still get an error:

/home/andre/Arduino/arduino-1.8.10/arduino-builder -dump-prefs -logger=machine -hardware /home/andre/Arduino/arduino-1.8.10/hardware -hardware /home/andre/.arduino15/packages -hardware /home/andre/Arduino/projects/hardware -tools /home/andre/Arduino/arduino-1.8.10/tools-builder -tools /home/andre/Arduino/arduino-1.8.10/hardware/tools/avr -tools /home/andre/.arduino15/packages -built-in-libraries /home/andre/Arduino/arduino-1.8.10/libraries -libraries /home/andre/Arduino/projects/libraries -fqbn=STM32:stm32:GenF1:pnum=BLUEPILL_F103C8,upload_method=swdMethod,xserial=generic,usb=CDCgen,xusb=FS,opt=osstd,rtlib=nano -ide-version=10810 -build-path /tmp/arduino -warnings=default -build-cache /tmp/arduino_cache_732036 -prefs=build.warn_data_percentage=75 -prefs=runtime.tools.arm-none-eabi-gcc.path=/home/andre/.arduino15/packages/STM32/tools/arm-none-eabi-gcc/8.2.1-1.7 -prefs=runtime.tools.arm-none-eabi-gcc-8.2.1-1.7.path=/home/andre/.arduino15/packages/STM32/tools/arm-none-eabi-gcc/8.2.1-1.7 -prefs=runtime.tools.STM32Tools.path=/home/andre/.arduino15/packages/STM32/tools/STM32Tools/1.3.1 -prefs=runtime.tools.STM32Tools-1.3.1.path=/home/andre/.arduino15/packages/STM32/tools/STM32Tools/1.3.1 -prefs=runtime.tools.CMSIS.path=/home/andre/.arduino15/packages/STM32/tools/CMSIS/5.5.1 -prefs=runtime.tools.CMSIS-5.5.1.path=/home/andre/.arduino15/packages/STM32/tools/CMSIS/5.5.1 -verbose /home/andre/Arduino/projects/temp-AnalogReadSerial/temp-AnalogReadSerial.ino
/home/andre/Arduino/arduino-1.8.10/arduino-builder -compile -logger=machine -hardware /home/andre/Arduino/arduino-1.8.10/hardware -hardware /home/andre/.arduino15/packages -hardware /home/andre/Arduino/projects/hardware -tools /home/andre/Arduino/arduino-1.8.10/tools-builder -tools /home/andre/Arduino/arduino-1.8.10/hardware/tools/avr -tools /home/andre/.arduino15/packages -built-in-libraries /home/andre/Arduino/arduino-1.8.10/libraries -libraries /home/andre/Arduino/projects/libraries -fqbn=STM32:stm32:GenF1:pnum=BLUEPILL_F103C8,upload_method=swdMethod,xserial=generic,usb=CDCgen,xusb=FS,opt=osstd,rtlib=nano -ide-version=10810 -build-path /tmp/arduino -warnings=default -build-cache /tmp/arduino_cache_732036 -prefs=build.warn_data_percentage=75 -prefs=runtime.tools.arm-none-eabi-gcc.path=/home/andre/.arduino15/packages/STM32/tools/arm-none-eabi-gcc/8.2.1-1.7 -prefs=runtime.tools.arm-none-eabi-gcc-8.2.1-1.7.path=/home/andre/.arduino15/packages/STM32/tools/arm-none-eabi-gcc/8.2.1-1.7 -prefs=runtime.tools.STM32Tools.path=/home/andre/.arduino15/packages/STM32/tools/STM32Tools/1.3.1 -prefs=runtime.tools.STM32Tools-1.3.1.path=/home/andre/.arduino15/packages/STM32/tools/STM32Tools/1.3.1 -prefs=runtime.tools.CMSIS.path=/home/andre/.arduino15/packages/STM32/tools/CMSIS/5.5.1 -prefs=runtime.tools.CMSIS-5.5.1.path=/home/andre/.arduino15/packages/STM32/tools/CMSIS/5.5.1 -verbose /home/andre/Arduino/projects/temp-AnalogReadSerial/temp-AnalogReadSerial.ino
Using board 'GenF1' from platform in folder: /home/andre/.arduino15/packages/STM32/hardware/stm32/1.7.0
Using core 'arduino' from platform in folder: /home/andre/.arduino15/packages/STM32/hardware/stm32/1.7.0
bash -c "[ -f /home/andre/Arduino/projects/temp-AnalogReadSerial/build_opt.h ] || (mkdir -p /tmp/arduino/sketch && touch /tmp/arduino/sketch/build_opt.h)"
Detecting libraries used...
/home/andre/.arduino15/packages/STM32/tools/arm-none-eabi-gcc/8.2.1-1.7/bin/arm-none-eabi-g++ -mcpu=cortex-m3 -mthumb @/tmp/arduino/sketch/build_opt.h -c -Os -w -std=gnu++14 -ffunction-sections -fdata-sections -nostdlib -fno-threadsafe-statics --param max-inline-insns-single=500 -fno-rtti -fno-exceptions -fno-use-cxa-atexit -I/home/andre/Arduino/projects/temp-AnalogReadSerial -I/home/andre/.arduino15/packages/STM32/hardware/stm32/1.7.0/cores/arduino/avr -I/home/andre/.arduino15/packages/STM32/hardware/stm32/1.7.0/cores/arduino/stm32 -I/home/andre/.arduino15/packages/STM32/hardware/stm32/1.7.0/cores/arduino/stm32/LL -I/home/andre/.arduino15/packages/STM32/hardware/stm32/1.7.0/cores/arduino/stm32/usb -I/home/andre/.arduino15/packages/STM32/hardware/stm32/1.7.0/cores/arduino/stm32/usb/hid -I/home/andre/.arduino15/packages/STM32/hardware/stm32/1.7.0/cores/arduino/stm32/usb/cdc -I/home/andre/.arduino15/packages/STM32/hardware/stm32/1.7.0/system/Drivers/STM32F1xx_HAL_Driver/Inc/ -I/home/andre/.arduino15/packages/STM32/hardware/stm32/1.7.0/system/Drivers/STM32F1xx_HAL_Driver/Src/ -I/home/andre/.arduino15/packages/STM32/hardware/stm32/1.7.0/system/STM32F1xx/ -I/home/andre/.arduino15/packages/STM32/hardware/stm32/1.7.0/system/Middlewares/ST/STM32_USB_Device_Library/Core/Inc -I/home/andre/.arduino15/packages/STM32/hardware/stm32/1.7.0/system/Middlewares/ST/STM32_USB_Device_Library/Core/Src -w -x c++ -E -CC -DSTM32F1xx -DARDUINO=10810 -DARDUINO_BLUEPILL_F103C8 -DARDUINO_ARCH_STM32 "-DBOARD_NAME=\"BLUEPILL_F103C8\"" -DSTM32F103xB -DUSBCON -DUSBD_VID=0x0483 "-DUSB_MANUFACTURER=\"Unknown\"" "-DUSB_PRODUCT=\"BLUEPILL_F103C8\"" -DHAL_PCD_MODULE_ENABLED -DUSBD_USE_CDC -DHAL_UART_MODULE_ENABLED -I/home/andre/.arduino15/packages/STM32/tools/CMSIS/5.5.1/CMSIS/Core/Include/ -I/home/andre/.arduino15/packages/STM32/hardware/stm32/1.7.0/system/Drivers/CMSIS/Device/ST/STM32F1xx/Include/ -I/home/andre/.arduino15/packages/STM32/hardware/stm32/1.7.0/system/Drivers/CMSIS/Device/ST/STM32F1xx/Source/Templates/gcc/ -I/home/andre/.arduino15/packages/STM32/hardware/stm32/1.7.0/cores/arduino -I/home/andre/.arduino15/packages/STM32/hardware/stm32/1.7.0/variants/PILL_F103XX /tmp/arduino/sketch/temp-AnalogReadSerial.ino.cpp -o /dev/null
Generating function prototypes...
/home/andre/.arduino15/packages/STM32/tools/arm-none-eabi-gcc/8.2.1-1.7/bin/arm-none-eabi-g++ -mcpu=cortex-m3 -mthumb @/tmp/arduino/sketch/build_opt.h -c -Os -w -std=gnu++14 -ffunction-sections -fdata-sections -nostdlib -fno-threadsafe-statics --param max-inline-insns-single=500 -fno-rtti -fno-exceptions -fno-use-cxa-atexit -I/home/andre/Arduino/projects/temp-AnalogReadSerial -I/home/andre/.arduino15/packages/STM32/hardware/stm32/1.7.0/cores/arduino/avr -I/home/andre/.arduino15/packages/STM32/hardware/stm32/1.7.0/cores/arduino/stm32 -I/home/andre/.arduino15/packages/STM32/hardware/stm32/1.7.0/cores/arduino/stm32/LL -I/home/andre/.arduino15/packages/STM32/hardware/stm32/1.7.0/cores/arduino/stm32/usb -I/home/andre/.arduino15/packages/STM32/hardware/stm32/1.7.0/cores/arduino/stm32/usb/hid -I/home/andre/.arduino15/packages/STM32/hardware/stm32/1.7.0/cores/arduino/stm32/usb/cdc -I/home/andre/.arduino15/packages/STM32/hardware/stm32/1.7.0/system/Drivers/STM32F1xx_HAL_Driver/Inc/ -I/home/andre/.arduino15/packages/STM32/hardware/stm32/1.7.0/system/Drivers/STM32F1xx_HAL_Driver/Src/ -I/home/andre/.arduino15/packages/STM32/hardware/stm32/1.7.0/system/STM32F1xx/ -I/home/andre/.arduino15/packages/STM32/hardware/stm32/1.7.0/system/Middlewares/ST/STM32_USB_Device_Library/Core/Inc -I/home/andre/.arduino15/packages/STM32/hardware/stm32/1.7.0/system/Middlewares/ST/STM32_USB_Device_Library/Core/Src -w -x c++ -E -CC -DSTM32F1xx -DARDUINO=10810 -DARDUINO_BLUEPILL_F103C8 -DARDUINO_ARCH_STM32 "-DBOARD_NAME=\"BLUEPILL_F103C8\"" -DSTM32F103xB -DUSBCON -DUSBD_VID=0x0483 "-DUSB_MANUFACTURER=\"Unknown\"" "-DUSB_PRODUCT=\"BLUEPILL_F103C8\"" -DHAL_PCD_MODULE_ENABLED -DUSBD_USE_CDC -DHAL_UART_MODULE_ENABLED -I/home/andre/.arduino15/packages/STM32/tools/CMSIS/5.5.1/CMSIS/Core/Include/ -I/home/andre/.arduino15/packages/STM32/hardware/stm32/1.7.0/system/Drivers/CMSIS/Device/ST/STM32F1xx/Include/ -I/home/andre/.arduino15/packages/STM32/hardware/stm32/1.7.0/system/Drivers/CMSIS/Device/ST/STM32F1xx/Source/Templates/gcc/ -I/home/andre/.arduino15/packages/STM32/hardware/stm32/1.7.0/cores/arduino -I/home/andre/.arduino15/packages/STM32/hardware/stm32/1.7.0/variants/PILL_F103XX /tmp/arduino/sketch/temp-AnalogReadSerial.ino.cpp -o /tmp/arduino/preproc/ctags_target_for_gcc_minus_e.cpp
/home/andre/Arduino/arduino-1.8.10/tools-builder/ctags/5.8-arduino11/ctags -u --language-force=c++ -f - --c++-kinds=svpf --fields=KSTtzns --line-directives /tmp/arduino/preproc/ctags_target_for_gcc_minus_e.cpp
Compiling sketch...
/home/andre/.arduino15/packages/STM32/tools/arm-none-eabi-gcc/8.2.1-1.7/bin/arm-none-eabi-g++ -mcpu=cortex-m3 -mthumb @/tmp/arduino/sketch/build_opt.h -c -Os -std=gnu++14 -ffunction-sections -fdata-sections -nostdlib -fno-threadsafe-statics --param max-inline-insns-single=500 -fno-rtti -fno-exceptions -fno-use-cxa-atexit -MMD -I/home/andre/Arduino/projects/temp-AnalogReadSerial -I/home/andre/.arduino15/packages/STM32/hardware/stm32/1.7.0/cores/arduino/avr -I/home/andre/.arduino15/packages/STM32/hardware/stm32/1.7.0/cores/arduino/stm32 -I/home/andre/.arduino15/packages/STM32/hardware/stm32/1.7.0/cores/arduino/stm32/LL -I/home/andre/.arduino15/packages/STM32/hardware/stm32/1.7.0/cores/arduino/stm32/usb -I/home/andre/.arduino15/packages/STM32/hardware/stm32/1.7.0/cores/arduino/stm32/usb/hid -I/home/andre/.arduino15/packages/STM32/hardware/stm32/1.7.0/cores/arduino/stm32/usb/cdc -I/home/andre/.arduino15/packages/STM32/hardware/stm32/1.7.0/system/Drivers/STM32F1xx_HAL_Driver/Inc/ -I/home/andre/.arduino15/packages/STM32/hardware/stm32/1.7.0/system/Drivers/STM32F1xx_HAL_Driver/Src/ -I/home/andre/.arduino15/packages/STM32/hardware/stm32/1.7.0/system/STM32F1xx/ -I/home/andre/.arduino15/packages/STM32/hardware/stm32/1.7.0/system/Middlewares/ST/STM32_USB_Device_Library/Core/Inc -I/home/andre/.arduino15/packages/STM32/hardware/stm32/1.7.0/system/Middlewares/ST/STM32_USB_Device_Library/Core/Src -DSTM32F1xx -DARDUINO=10810 -DARDUINO_BLUEPILL_F103C8 -DARDUINO_ARCH_STM32 "-DBOARD_NAME=\"BLUEPILL_F103C8\"" -DSTM32F103xB -DUSBCON -DUSBD_VID=0x0483 "-DUSB_MANUFACTURER=\"Unknown\"" "-DUSB_PRODUCT=\"BLUEPILL_F103C8\"" -DHAL_PCD_MODULE_ENABLED -DUSBD_USE_CDC -DHAL_UART_MODULE_ENABLED -I/home/andre/.arduino15/packages/STM32/tools/CMSIS/5.5.1/CMSIS/Core/Include/ -I/home/andre/.arduino15/packages/STM32/hardware/stm32/1.7.0/system/Drivers/CMSIS/Device/ST/STM32F1xx/Include/ -I/home/andre/.arduino15/packages/STM32/hardware/stm32/1.7.0/system/Drivers/CMSIS/Device/ST/STM32F1xx/Source/Templates/gcc/ -I/home/andre/.arduino15/packages/STM32/hardware/stm32/1.7.0/cores/arduino -I/home/andre/.arduino15/packages/STM32/hardware/stm32/1.7.0/variants/PILL_F103XX /tmp/arduino/sketch/temp-AnalogReadSerial.ino.cpp -o /tmp/arduino/sketch/temp-AnalogReadSerial.ino.cpp.o
Compiling libraries...
Compiling core...
Using previously compiled file: /tmp/arduino/core/PeripheralPins.c.o
Using previously compiled file: /tmp/arduino/core/variant.cpp.o
Using precompiled core: /tmp/arduino_cache_732036/core/core_d2d4f59cd5ddb04efe7cc8993937479a.a
Linking everything together...
/home/andre/.arduino15/packages/STM32/tools/arm-none-eabi-gcc/8.2.1-1.7/bin/arm-none-eabi-gcc -mcpu=cortex-m3 -mthumb -Os --specs=nano.specs -Wl,--defsym=LD_FLASH_OFFSET=0 -Wl,--defsym=LD_MAX_SIZE=65536 -Wl,--defsym=LD_MAX_DATA_SIZE=20480 -Wl,--cref -Wl,--check-sections -Wl,--gc-sections -Wl,--entry=Reset_Handler -Wl,--unresolved-symbols=report-all -Wl,--warn-common -T/home/andre/.arduino15/packages/STM32/hardware/stm32/1.7.0/variants/PILL_F103XX/ldscript.ld -Wl,-Map,/tmp/arduino/temp-AnalogReadSerial.ino.map -L/home/andre/.arduino15/packages/STM32/tools/CMSIS/5.5.1/CMSIS/DSP/Lib/GCC/ -larm_cortexM3l_math -o /tmp/arduino/temp-AnalogReadSerial.ino.elf -L/tmp/arduino -Wl,--start-group /tmp/arduino/sketch/temp-AnalogReadSerial.ino.cpp.o /tmp/arduino/core/PeripheralPins.c.o /tmp/arduino/core/variant.cpp.o -Wl,--whole-archive /tmp/arduino_cache_732036/core/core_d2d4f59cd5ddb04efe7cc8993937479a.a -Wl,--no-whole-archive -lc -Wl,--end-group -lm -lgcc -lstdc++
/home/andre/.arduino15/packages/STM32/tools/arm-none-eabi-gcc/8.2.1-1.7/bin/../lib/gcc/arm-none-eabi/8.2.1/../../../../arm-none-eabi/bin/ld: /tmp/arduino/sketch/temp-AnalogReadSerial.ino.cpp.o: in function `setup':
temp-AnalogReadSerial.ino.cpp:(.text.setup+0x2c): undefined reference to `Serial2'
/home/andre/.arduino15/packages/STM32/tools/arm-none-eabi-gcc/8.2.1-1.7/bin/../lib/gcc/arm-none-eabi/8.2.1/../../../../arm-none-eabi/bin/ld: temp-AnalogReadSerial.ino.cpp:(.text.setup+0x30): undefined reference to `Serial3'
collect2: error: ld returned 1 exit status
exit status 1
Error compiling for board Generic STM32F1 series.

BTW: I absolutely LOVE that you already added a half-duplex mode. Is inverted mode possible too ?

[fpistm]

I've just tested and it works.
Regarding your log:
Using previously compiled file:
As it is specified in the wiki for build_opt.h, if you already build before add it then it is ignored.
Close and reopen Arduino IDE.

[AndKe]

I am embarrassed, but happy. - thanks for the swift help