[Keyboard] Add zvecr/split_blackpill (#9166)

* Add split_blackpill keyboard

* Add RGB config

* tidy up rules

* fix usage of layer_state_t

* Apply suggestions from code review

* Apply suggestions from code review

* Apply suggestions from code review

* Add configurator support

keyboards/zvecr/split_blackpill/rules.mk

@@ -0,0 +1,37 @@
+# MCU name
+MCU = STM32F103
+
+# GENERIC STM32F103C8T6 board - stm32duino bootloader
+OPT_DEFS = -DCORTEX_VTOR_INIT=0x2000
+MCU_LDSCRIPT = STM32F103x8_stm32duino_bootloader
+BOARD = STM32_F103_STM32DUINO
+STM32_BOOTLOADER_ADDRESS = 0x80000000
+
+DFU_ARGS = -d 1eaf:0003 -a2 -R
+DFU_SUFFIX_ARGS = -v 1eaf -p 0003
+
+# Build Options
+#   change yes to no to disable
+#
+BOOTMAGIC_ENABLE = lite     # Virtual DIP switch configuration
+MOUSEKEY_ENABLE = yes       # Mouse keys
+EXTRAKEY_ENABLE = yes       # Audio control and System control
+CONSOLE_ENABLE = no         # Console for debug
+COMMAND_ENABLE = no         # Commands for debug and configuration
+# Do not enable SLEEP_LED_ENABLE. it uses the same timer as BACKLIGHT_ENABLE
+SLEEP_LED_ENABLE = no       # Breathing sleep LED during USB suspend
+# if this doesn't work, see here: https://github.com/tmk/tmk_keyboard/wiki/FAQ#nkro-doesnt-work
+NKRO_ENABLE = yes           # USB Nkey Rollover
+BACKLIGHT_ENABLE = no       # Enable keyboard backlight functionality
+RGBLIGHT_ENABLE = yes       # Enable keyboard RGB underglow
+MIDI_ENABLE = no            # MIDI support
+BLUETOOTH_ENABLE = no       # Enable Bluetooth with the Adafruit EZ-Key HID
+AUDIO_ENABLE = no           # Audio output
+FAUXCLICKY_ENABLE = no      # Use buzzer to emulate clicky switches
+
+SPLIT_KEYBOARD = yes
+SERIAL_DRIVER = usart
+WS2812_DRIVER = pwm
+OPT_DEFS += -DSTM32_DMA_REQUIRED=TRUE
+
+LAYOUTS = ortho_4x12