Add example stm32 bluepill setup

platformio.ini

@@ -39,4 +39,12 @@ build_flags = -D MCU_PICO
 platform = ststm32
 board = bluepill_f103c8
 upload_protocol = stlink
-build_flags = -D MCU_BLUEPILL
+build_flags =
+  -D MCU_BLUEPILL
+  -D PIO_FRAMEWORK_ARDUINO_ENABLE_CDC
+  -D USBCON
+  -D USBD_VID=0x0483
+  -D USBD_PID=0x5740
+  -D USB_MANUFACTURER="Unknown"
+  -D USB_PRODUCT="\"BLUEPILL_F103C8\""
+  -D HAL_PCD_MODULE_ENABLED

src/boards.h

@@ -1,10 +1,12 @@
 #ifdef BOARD_AUTO
     #ifdef MCU_LEONARDO
         #define BOARD_SANGABOARDv3
-        #define BOARD_STRING "Sangaboard v0.3"
-    #elif defined(MCU_NANO) || defined(MCU_PICO) || defined(MCU_BLUEPILL)
+    #elif defined(MCU_NANO)
         #define BOARD_SANGABOARDv2
-        #define BOARD_STRING "Sangaboard v0.2"
+    #elif defined(MCU_BLUEPILL)
+        #define BOARD_CUSTOM_BLUEPILL
+    #elif defined(MCU_PICO)
+        #define BOARD_CUSTOM
     #else
         #error "Invalid build config - must specify MCU type"
     #endif
@@ -28,8 +30,16 @@
     #define ENDSTOPS_PULLUPS true
     #define WIRING_ENDSTOPS_MIN {A0,A1,A2}
     #define WIRING_ENDSTOPS_MAX {A3,A4,A5}
+#elif defined(BOARD_CUSTOM_BLUEPILL)
+    #define BOARD_STRING "Custom Bluepill board"
+    #define WIRING_MOTOR_X PB11, PB10, PB1, PB0
+    #define WIRING_MOTOR_Y PA7, PA6, PA5, PA4
+    #define WIRING_MOTOR_Z PA3, PA2, PA1, PA0
+    #define ENDSTOPS_INVERT false
+    #define ENDSTOPS_PULLUPS true
+    #define WIRING_ENDSTOPS_MIN {A0,A1,A2}
+    #define WIRING_ENDSTOPS_MAX {A3,A4,A5}
 #else
-    //custom board
     #define BOARD_STRING "Custom board"
     #define WIRING_MOTOR_X 13, 12, 11, 10
     #define WIRING_MOTOR_Y 9, 8, 7, 6