Support for STM32L0 MCUs and Dragino LGT92 device (#1561)

machine/stm32l0: add support for stm32l0 family and Dragino LGT92 Board

src/machine/board_lgt92.go

@@ -0,0 +1,80 @@
+// +build lgt92
+
+package machine
+
+import (
+	"device/stm32"
+	"runtime/interrupt"
+)
+
+const (
+	LED1 = PA12
+	LED2 = PA8
+	LED3 = PA11
+
+	LED_RED   = LED1
+	LED_BLUE  = LED2
+	LED_GREEN = LED3
+
+	// Default led
+	LED = LED1
+
+	BUTTON = PB14
+
+	// LG GPS module
+	GPS_STANDBY_PIN = PB3
+	GPS_RESET_PIN   = PB4
+	GPS_POWER_PIN   = PB5
+
+	MEMS_ACCEL_CS   = PE3
+	MEMS_ACCEL_INT1 = PE0
+	MEMS_ACCEL_INT2 = PE1
+
+	// SPI
+	SPI1_SCK_PIN = PA5
+	SPI1_SDI_PIN = PA6
+	SPI1_SDO_PIN = PA7
+	SPI0_SCK_PIN = SPI1_SCK_PIN
+	SPI0_SDI_PIN = SPI1_SDI_PIN
+	SPI0_SDO_PIN = SPI1_SDO_PIN
+
+	// LORA RFM95 Radio
+	RFM95_DIO0_PIN = PC13
+
+	//TinyGo UART is MCU LPUSART1
+	UART_RX_PIN = PA13
+	UART_TX_PIN = PA14
+
+	//TinyGo UART1 is MCU USART1
+	UART1_RX_PIN = PB6
+	UART1_TX_PIN = PB7
+)
+
+var (
+
+	// Console UART (LPUSART1)
+	UART0 = UART{
+		Buffer:          NewRingBuffer(),
+		Bus:             stm32.LPUSART1,
+		AltFuncSelector: 6,
+	}
+
+	// Gps UART
+	UART1 = UART{
+		Buffer:          NewRingBuffer(),
+		Bus:             stm32.USART1,
+		AltFuncSelector: 0,
+	}
+
+	// SPI
+	SPI0 = SPI{
+		Bus: stm32.SPI1,
+	}
+	SPI1 = &SPI0
+)
+
+func init() {
+	// Enable UARTs Interrupts
+	UART0.Interrupt = interrupt.New(stm32.IRQ_AES_RNG_LPUART1, UART0.handleInterrupt)
+	UART1.Interrupt = interrupt.New(stm32.IRQ_USART1, UART1.handleInterrupt)
+}