Support for STM32L0 MCUs and Dragino LGT92 device

Makefile

@@ -295,6 +295,8 @@ smoketest:
 	@$(MD5SUM) test.hex
 	$(TINYGO) build -size short -o test.hex -target=pinetime-devkit0    examples/blinky1
 	@$(MD5SUM) test.hex
+	$(TINYGO) build -size short -o test.hex -target=lgt92    examples/blinky1
+	@$(MD5SUM) test.hex
 	$(TINYGO) build -size short -o test.hex -target=x9pro               examples/blinky1
 	@$(MD5SUM) test.hex
 	$(TINYGO) build -size short -o test.hex -target=pca10056-s140v7     examples/blinky1

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)
+}

src/machine/i2c.go

@@ -1,4 +1,4 @@
-// +build avr nrf sam stm32,!stm32f407,!stm32f7x2 fe310 k210
+// +build avr nrf sam stm32,!stm32f407,!stm32f7x2,!stm32l0 fe310 k210
 
 package machine
 

src/machine/machine_stm32_i2c.go

@@ -1,4 +1,4 @@
-// +build stm32,!stm32f103xx,!stm32f407,!stm32f7x2
+// +build stm32,!stm32f103xx,!stm32f407,!stm32f7x2,!stm32l0
 
 package machine
 

src/machine/machine_stm32_uart.go

@@ -1,4 +1,4 @@
-// +build stm32,!stm32f7
+// +build stm32,!stm32f7,!stm32l0
 
 package machine
 

src/machine/machine_stm32l0.go

@@ -0,0 +1,288 @@
+// +build stm32l0
+
+package machine
+
+// Peripheral abstraction layer for the stm32l0
+
+import (
+	"device/stm32"
+	"runtime/interrupt"
+	"unsafe"
+)
+
+func CPUFrequency() uint32 {
+	return 32000000
+}
+
+const (
+	PA0  = portA + 0
+	PA1  = portA + 1
+	PA2  = portA + 2
+	PA3  = portA + 3
+	PA4  = portA + 4
+	PA5  = portA + 5
+	PA6  = portA + 6
+	PA7  = portA + 7
+	PA8  = portA + 8
+	PA9  = portA + 9
+	PA10 = portA + 10
+	PA11 = portA + 11
+	PA12 = portA + 12
+	PA13 = portA + 13
+	PA14 = portA + 14
+	PA15 = portA + 15
+
+	PB0  = portB + 0
+	PB1  = portB + 1
+	PB2  = portB + 2
+	PB3  = portB + 3
+	PB4  = portB + 4
+	PB5  = portB + 5
+	PB6  = portB + 6
+	PB7  = portB + 7
+	PB8  = portB + 8
+	PB9  = portB + 9
+	PB10 = portB + 10
+	PB11 = portB + 11
+	PB12 = portB + 12
+	PB13 = portB + 13
+	PB14 = portB + 14
+	PB15 = portB + 15
+
+	PC0  = portC + 0
+	PC1  = portC + 1
+	PC2  = portC + 2
+	PC3  = portC + 3
+	PC4  = portC + 4
+	PC5  = portC + 5
+	PC6  = portC + 6
+	PC7  = portC + 7
+	PC8  = portC + 8
+	PC9  = portC + 9
+	PC10 = portC + 10
+	PC11 = portC + 11
+	PC12 = portC + 12
+	PC13 = portC + 13
+	PC14 = portC + 14
+	PC15 = portC + 15
+
+	PD0  = portD + 0
+	PD1  = portD + 1
+	PD2  = portD + 2
+	PD3  = portD + 3
+	PD4  = portD + 4
+	PD5  = portD + 5
+	PD6  = portD + 6
+	PD7  = portD + 7
+	PD8  = portD + 8
+	PD9  = portD + 9
+	PD10 = portD + 10
+	PD11 = portD + 11
+	PD12 = portD + 12
+	PD13 = portD + 13
+	PD14 = portD + 14
+	PD15 = portD + 15
+
+	PE0  = portE + 0
+	PE1  = portE + 1
+	PE2  = portE + 2
+	PE3  = portE + 3
+	PE4  = portE + 4
+	PE5  = portE + 5
+	PE6  = portE + 6
+	PE7  = portE + 7
+	PE8  = portE + 8
+	PE9  = portE + 9
+	PE10 = portE + 10
+	PE11 = portE + 11
+	PE12 = portE + 12
+	PE13 = portE + 13
+	PE14 = portE + 14
+	PE15 = portE + 15
+
+	PH0 = portH + 0
+	PH1 = portH + 1
+)
+
+func (p Pin) getPort() *stm32.GPIO_Type {
+	switch p / 16 {
+	case 0:
+		return stm32.GPIOA
+	case 1:
+		return stm32.GPIOB
+	case 2:
+		return stm32.GPIOC
+	case 3:
+		return stm32.GPIOD
+	case 4:
+		return stm32.GPIOE
+	case 7:
+		return stm32.GPIOH
+	default:
+		panic("machine: unknown port")
+	}
+}
+
+// enableClock enables the clock for this desired GPIO port.
+func (p Pin) enableClock() {
+	switch p / 16 {
+	case 0:
+		stm32.RCC.IOPENR.SetBits(stm32.RCC_IOPENR_IOPAEN)
+	case 1:
+		stm32.RCC.IOPENR.SetBits(stm32.RCC_IOPENR_IOPBEN)
+	case 2:
+		stm32.RCC.IOPENR.SetBits(stm32.RCC_IOPENR_IOPCEN)
+	case 3:
+		stm32.RCC.IOPENR.SetBits(stm32.RCC_IOPENR_IOPDEN)
+	case 4:
+		stm32.RCC.IOPENR.SetBits(stm32.RCC_IOPENR_IOPEEN)
+	case 7:
+		stm32.RCC.IOPENR.SetBits(stm32.RCC_IOPENR_IOPHEN)
+	default:
+		panic("machine: unknown port")
+	}
+}
+
+// Enable peripheral clock
+func enableAltFuncClock(bus unsafe.Pointer) {
+	switch bus {
+	case unsafe.Pointer(stm32.DAC): // DAC interface clock enable
+		stm32.RCC.APB1ENR.SetBits(stm32.RCC_APB1ENR_DACEN)
+	case unsafe.Pointer(stm32.PWR): // Power interface clock enable
+		stm32.RCC.APB1ENR.SetBits(stm32.RCC_APB1ENR_PWREN)
+	case unsafe.Pointer(stm32.I2C3): // I2C3 clock enable
+		stm32.RCC.APB1ENR.SetBits(stm32.RCC_APB1ENR_I2C3EN)
+	case unsafe.Pointer(stm32.I2C2): // I2C2 clock enable
+		stm32.RCC.APB1ENR.SetBits(stm32.RCC_APB1ENR_I2C2EN)
+	case unsafe.Pointer(stm32.I2C1): // I2C1 clock enable
+		stm32.RCC.APB1ENR.SetBits(stm32.RCC_APB1ENR_I2C1EN)
+	case unsafe.Pointer(stm32.USART5): // UART5 clock enable
+		stm32.RCC.APB1ENR.SetBits(stm32.RCC_APB1ENR_USART5EN)
+	case unsafe.Pointer(stm32.USART4): // UART4 clock enable
+		stm32.RCC.APB1ENR.SetBits(stm32.RCC_APB1ENR_USART4EN)
+	case unsafe.Pointer(stm32.USART2): // USART2 clock enable
+		stm32.RCC.APB1ENR.SetBits(stm32.RCC_APB1ENR_USART2EN)
+	case unsafe.Pointer(stm32.SPI2): // SPI2 clock enable
+		stm32.RCC.APB1ENR.SetBits(stm32.RCC_APB1ENR_SPI2EN)
+	case unsafe.Pointer(stm32.LPUSART1): // LPUSART1 clock enable
+		stm32.RCC.APB1ENR.SetBits(stm32.RCC_APB1ENR_LPUART1EN)
+	case unsafe.Pointer(stm32.WWDG): // Window watchdog clock enable
+		stm32.RCC.APB1ENR.SetBits(stm32.RCC_APB1ENR_WWDGEN)
+	case unsafe.Pointer(stm32.TIM7): // TIM7 clock enable
+		stm32.RCC.APB1ENR.SetBits(stm32.RCC_APB1ENR_TIM7EN)
+	case unsafe.Pointer(stm32.TIM6): // TIM6 clock enable
+		stm32.RCC.APB1ENR.SetBits(stm32.RCC_APB1ENR_TIM6EN)
+	case unsafe.Pointer(stm32.TIM3): // TIM3 clock enable
+		stm32.RCC.APB1ENR.SetBits(stm32.RCC_APB1ENR_TIM3EN)
+	case unsafe.Pointer(stm32.TIM2): // TIM2 clock enable
+		stm32.RCC.APB1ENR.SetBits(stm32.RCC_APB1ENR_TIM2EN)
+	case unsafe.Pointer(stm32.SYSCFG_COMP): // System configuration controller clock enable
+		stm32.RCC.APB2ENR.SetBits(stm32.RCC_APB2ENR_SYSCFGEN)
+	case unsafe.Pointer(stm32.SPI1): // SPI1 clock enable
+		stm32.RCC.APB2ENR.SetBits(stm32.RCC_APB2ENR_SPI1EN)
+	case unsafe.Pointer(stm32.ADC): // ADC clock enable
+		stm32.RCC.APB2ENR.SetBits(stm32.RCC_APB2ENR_ADCEN)
+	case unsafe.Pointer(stm32.USART1): // USART1 clock enable
+		stm32.RCC.APB2ENR.SetBits(stm32.RCC_APB2ENR_USART1EN)
+	}
+}
+
+//---------- UART related types and code
+
+// UART representation
+type UART struct {
+	Buffer          *RingBuffer
+	Bus             *stm32.USART_Type
+	Interrupt       interrupt.Interrupt
+	AltFuncSelector stm32.AltFunc
+}
+
+// Configure the UART.
+func (uart UART) configurePins(config UARTConfig) {
+	// enable the alternate functions on the TX and RX pins
+	config.TX.ConfigureAltFunc(PinConfig{Mode: PinModeUARTTX}, uart.AltFuncSelector)
+	config.RX.ConfigureAltFunc(PinConfig{Mode: PinModeUARTRX}, uart.AltFuncSelector)
+}
+
+// UART baudrate calc based on the bus and clockspeed
+func (uart UART) getBaudRateDivisor(baudRate uint32) uint32 {
+	var clock, rate uint32
+	switch uart.Bus {
+	case stm32.LPUSART1:
+		clock = CPUFrequency() / 2 // APB1 Frequency
+		rate = uint32((256 * clock) / baudRate)
+	case stm32.USART1:
+		clock = CPUFrequency() / 2 // APB2 Frequency
+		rate = uint32(clock / baudRate)
+	case stm32.USART2:
+		clock = CPUFrequency() / 2 // APB1 Frequency
+		rate = uint32(clock / baudRate)
+	}
+
+	return rate
+}
+
+//---------- SPI related types and code
+
+// SPI on the STM32Fxxx using MODER / alternate function pins
+type SPI struct {
+	Bus             *stm32.SPI_Type
+	AltFuncSelector stm32.AltFunc
+}
+
+// Set baud rate for SPI
+func (spi SPI) getBaudRate(config SPIConfig) uint32 {
+	var conf uint32
+
+	localFrequency := config.Frequency
+
+	// Default
+	if config.Frequency == 0 {
+		config.Frequency = 4e6
+	}
+
+	if spi.Bus != stm32.SPI1 {
+		// Assume it's SPI2 or SPI3 on APB1 at 1/2 the clock frequency of APB2, so
+		//  we want to pretend to request 2x the baudrate asked for
+		localFrequency = localFrequency * 2
+	}
+
+	// set frequency dependent on PCLK prescaler. Since these are rather weird
+	// speeds due to the CPU freqency, pick a range up to that frquency for
+	// clients to use more human-understandable numbers, e.g. nearest 100KHz
+
+	// These are based on APB2 clock frquency (84MHz on the discovery board)
+	// TODO: also include the MCU/APB clock setting in the equation
+	switch {
+	case localFrequency < 328125:
+		conf = stm32.SPI_PCLK_256
+	case localFrequency < 656250:
+		conf = stm32.SPI_PCLK_128
+	case localFrequency < 1312500:
+		conf = stm32.SPI_PCLK_64
+	case localFrequency < 2625000:
+		conf = stm32.SPI_PCLK_32
+	case localFrequency < 5250000:
+		conf = stm32.SPI_PCLK_16
+	case localFrequency < 10500000:
+		conf = stm32.SPI_PCLK_8
+		// NOTE: many SPI components won't operate reliably (or at all) above 10MHz
+		// Check the datasheet of the part
+	case localFrequency < 21000000:
+		conf = stm32.SPI_PCLK_4
+	case localFrequency < 42000000:
+		conf = stm32.SPI_PCLK_2
+	default:
+		// None of the specific baudrates were selected; choose the lowest speed
+		conf = stm32.SPI_PCLK_256
+	}
+
+	return conf << stm32.SPI_CR1_BR_Pos
+}
+
+// Configure SPI pins for input output and clock
+func (spi SPI) configurePins(config SPIConfig) {
+	config.SCK.ConfigureAltFunc(PinConfig{Mode: PinModeSPICLK}, spi.AltFuncSelector)
+	config.SDO.ConfigureAltFunc(PinConfig{Mode: PinModeSPISDO}, spi.AltFuncSelector)
+	config.SDI.ConfigureAltFunc(PinConfig{Mode: PinModeSPISDI}, spi.AltFuncSelector)
+}