targets: add support for the MKS Robin Nano V3.x

Signed-off-by: Elias Naur <mail@eliasnaur.com>

GNUmakefile

@@ -717,6 +717,8 @@ ifneq ($(STM32), 0)
 	@$(MD5SUM) test.hex
 	$(TINYGO) build -size short -o test.hex -target=swan                examples/blinky1
 	@$(MD5SUM) test.hex
+	$(TINYGO) build -size short -o test.hex -target=mksnanov3           examples/blinky1
+	@$(MD5SUM) test.hex
 endif
 	$(TINYGO) build -size short -o test.hex -target=atmega328pb         examples/blinkm
 	@$(MD5SUM) test.hex

src/machine/board_mksnanov3.go

@@ -0,0 +1,109 @@
+//go:build mksnanov3
+
+// The MKS Robin Nano V3.X board.
+// Documented at https://github.com/makerbase-mks/MKS-Robin-Nano-V3.X.
+
+package machine
+
+import (
+	"device/stm32"
+	"runtime/interrupt"
+)
+
+// LED is also wired to the SD card card detect (CD) pin.
+const LED = PD12
+
+// UART pins
+const (
+	UART_TX_PIN = PB10
+	UART_RX_PIN = PB11
+)
+
+// EXP1 and EXP2 expansion ports for connecting
+// the MKS TS35 V2.0 expansion board.
+const (
+	BEEPER = EXP1_1
+
+	// LCD pins.
+	LCD_DC        = EXP1_8
+	LCD_CS        = EXP1_7
+	LCD_RS        = EXP1_4
+	LCD_BACKLIGHT = EXP1_3
+
+	// Touch pins. Note that some pins are shared with the
+	// LCD SPI1 interface.
+	TOUCH_CLK  = EXP2_2
+	TOUCH_CS   = EXP1_5
+	TOUCH_DIN  = EXP2_6
+	TOUCH_DOUT = EXP2_1
+	TOUCH_IRQ  = EXP1_6
+
+	BUTTON         = BUTTON_JOG
+	BUTTON_JOG     = EXP1_2
+	BUTTON_JOG_CCW = EXP2_3
+	BUTTON_JOG_CW  = EXP2_5
+
+	EXP1_1 = PC5
+	EXP1_2 = PE13
+	EXP1_3 = PD13
+	EXP1_4 = PC6
+	EXP1_5 = PE14
+	EXP1_6 = PE15
+	EXP1_7 = PD11
+	EXP1_8 = PD10
+
+	EXP2_1 = PA6
+	EXP2_2 = PA5
+	EXP2_3 = PE8
+	EXP2_4 = PE10
+	EXP2_5 = PE11
+	EXP2_6 = PA7
+	EXP2_7 = PE12
+)
+
+var (
+	UART3  = &_UART3
+	_UART3 = UART{
+		Buffer:            NewRingBuffer(),
+		Bus:               stm32.USART3,
+		TxAltFuncSelector: AF7_USART1_2_3,
+		RxAltFuncSelector: AF7_USART1_2_3,
+	}
+	DefaultUART = UART3
+)
+
+// set up RX IRQ handler. Follow similar pattern for other UARTx instances
+func init() {
+	UART3.Interrupt = interrupt.New(stm32.IRQ_USART3, _UART3.handleInterrupt)
+}
+
+// SPI pins
+const (
+	SPI1_SCK_PIN = EXP2_2
+	SPI1_SDI_PIN = EXP2_1
+	SPI1_SDO_PIN = EXP2_6
+	SPI0_SCK_PIN = SPI1_SCK_PIN
+	SPI0_SDI_PIN = SPI1_SDI_PIN
+	SPI0_SDO_PIN = SPI1_SDO_PIN
+)
+
+// Since the first interface is named SPI1, both SPI0 and SPI1 refer to SPI1.
+var (
+	SPI0 = SPI{
+		Bus:             stm32.SPI1,
+		AltFuncSelector: AF5_SPI1_SPI2,
+	}
+	SPI1 = &SPI0
+)
+
+const (
+	I2C0_SCL_PIN = PB6
+	I2C0_SDA_PIN = PB7
+)
+
+var (
+	I2C0 = &I2C{
+		Bus:             stm32.I2C1,
+		AltFuncSelector: AF4_I2C1_2_3,
+	}
+)

targets/mksnanov3.json

@@ -0,0 +1,12 @@
+{
+  "inherits": ["cortex-m4"],
+  "build-tags": ["mksnanov3", "stm32f407", "stm32f4", "stm32"],
+  "serial": "uart",
+  "linkerscript": "targets/stm32f407.ld",
+  "extra-files": [
+    "src/device/stm32/stm32f407.s"
+  ],
+  "flash-method": "openocd",
+  "openocd-interface": "stlink-v2",
+  "openocd-target": "stm32f4x"
+}