stm32: Harmonization of UART logic

src/machine/machine_stm32_f7_uart.go

@@ -1,62 +0,0 @@
-// +build stm32f7
-
-package machine
-
-// Peripheral abstraction layer for UARTs on the stm32 family.
-
-import (
-	"device/stm32"
-	"runtime/interrupt"
-	"unsafe"
-)
-
-// Configure the UART.
-func (uart UART) Configure(config UARTConfig) {
-	// Default baud rate to 115200.
-	if config.BaudRate == 0 {
-		config.BaudRate = 115200
-	}
-
-	// Set the GPIO pins to defaults if they're not set
-	if config.TX == 0 && config.RX == 0 {
-		config.TX = UART_TX_PIN
-		config.RX = UART_RX_PIN
-	}
-
-	// Enable USART clock
-	enableAltFuncClock(unsafe.Pointer(uart.Bus))
-
-	uart.configurePins(config)
-
-	// Set baud rate
-	uart.SetBaudRate(config.BaudRate)
-
-	// Enable USART port, tx, rx and rx interrupts
-	uart.Bus.CR1.Set(stm32.USART_CR1_TE | stm32.USART_CR1_RE | stm32.USART_CR1_RXNEIE | stm32.USART_CR1_UE)
-
-	// Enable RX IRQ
-	uart.Interrupt.SetPriority(0xc0)
-	uart.Interrupt.Enable()
-}
-
-// handleInterrupt should be called from the appropriate interrupt handler for
-// this UART instance.
-func (uart *UART) handleInterrupt(interrupt.Interrupt) {
-	uart.Receive(byte((uart.Bus.RDR.Get() & 0xFF)))
-}
-
-// SetBaudRate sets the communication speed for the UART. Defer to chip-specific
-// routines for calculation
-func (uart UART) SetBaudRate(br uint32) {
-	divider := uart.getBaudRateDivisor(br)
-	uart.Bus.BRR.Set(divider)
-}
-
-// WriteByte writes a byte of data to the UART.
-func (uart UART) WriteByte(c byte) error {
-	uart.Bus.TDR.Set(uint32(c))
-
-	for !uart.Bus.ISR.HasBits(stm32.USART_ISR_TXE) {
-	}
-	return nil
-}

src/machine/machine_stm32_l5_uart.go

@@ -1,62 +0,0 @@
-// +build stm32,stm32l5x2
-
-package machine
-
-// Peripheral abstraction layer for UARTs on the stm32 family.
-
-import (
-	"device/stm32"
-	"runtime/interrupt"
-	"unsafe"
-)
-
-// Configure the UART.
-func (uart UART) Configure(config UARTConfig) {
-	// Default baud rate to 115200.
-	if config.BaudRate == 0 {
-		config.BaudRate = 115200
-	}
-
-	// Set the GPIO pins to defaults if they're not set
-	if config.TX == 0 && config.RX == 0 {
-		config.TX = UART_TX_PIN
-		config.RX = UART_RX_PIN
-	}
-
-	// Enable USART clock
-	enableAltFuncClock(unsafe.Pointer(uart.Bus))
-
-	uart.configurePins(config)
-
-	// Set baud rate
-	uart.SetBaudRate(config.BaudRate)
-
-	// Enable USART port, tx, rx and rx interrupts
-	uart.Bus.CR1.Set(stm32.USART_CR1_TE | stm32.USART_CR1_RE | stm32.USART_CR1_RXNEIE | stm32.USART_CR1_UE)
-
-	// Enable RX IRQ
-	uart.Interrupt.SetPriority(0xc0)
-	uart.Interrupt.Enable()
-}
-
-// handleInterrupt should be called from the appropriate interrupt handler for
-// this UART instance.
-func (uart *UART) handleInterrupt(interrupt.Interrupt) {
-	uart.Receive(byte((uart.Bus.RDR.Get() & 0xFF)))
-}
-
-// SetBaudRate sets the communication speed for the UART. Defer to chip-specific
-// routines for calculation
-func (uart UART) SetBaudRate(br uint32) {
-	divider := uart.getBaudRateDivisor(br)
-	uart.Bus.BRR.Set(divider)
-}
-
-// WriteByte writes a byte of data to the UART.
-func (uart UART) WriteByte(c byte) error {
-	uart.Bus.TDR.Set(uint32(c))
-
-	for !uart.Bus.ISR.HasBits(stm32.USART_ISR_TXE) {
-	}
-	return nil
-}

src/machine/machine_stm32_uart.go

@@ -1,4 +1,4 @@
-// +build stm32,!stm32f7,!stm32l5x2,!stm32l0
+// +build stm32,!stm32l0
 
 package machine
 
@@ -7,11 +7,26 @@ package machine
 import (
 	"device/stm32"
 	"runtime/interrupt"
+	"runtime/volatile"
 	"unsafe"
 )
 
+// UART representation
+type UART struct {
+	Buffer          *RingBuffer
+	Bus             *stm32.USART_Type
+	Interrupt       interrupt.Interrupt
+	AltFuncSelector stm32.AltFunc
+
+	// Registers specific to the chip
+	rxReg       *volatile.Register32
+	txReg       *volatile.Register32
+	statusReg   *volatile.Register32
+	txEmptyFlag uint32
+}
+
 // Configure the UART.
-func (uart UART) Configure(config UARTConfig) {
+func (uart *UART) Configure(config UARTConfig) {
 	// Default baud rate to 115200.
 	if config.BaudRate == 0 {
 		config.BaudRate = 115200
@@ -23,6 +38,11 @@ func (uart UART) Configure(config UARTConfig) {
 		config.RX = UART_RX_PIN
 	}
 
+	// STM32 families have different, but compatible, registers for
+	// basic UART functions.  For each family populate the registers
+	// into `uart`.
+	uart.setRegisters()
+
 	// Enable USART clock
 	enableAltFuncClock(unsafe.Pointer(uart.Bus))
 
@@ -42,21 +62,21 @@ func (uart UART) Configure(config UARTConfig) {
 // handleInterrupt should be called from the appropriate interrupt handler for
 // this UART instance.
 func (uart *UART) handleInterrupt(interrupt.Interrupt) {
-	uart.Receive(byte((uart.Bus.DR.Get() & 0xFF)))
+	uart.Receive(byte((uart.rxReg.Get() & 0xFF)))
 }
 
 // SetBaudRate sets the communication speed for the UART. Defer to chip-specific
 // routines for calculation
-func (uart UART) SetBaudRate(br uint32) {
+func (uart *UART) SetBaudRate(br uint32) {
 	divider := uart.getBaudRateDivisor(br)
 	uart.Bus.BRR.Set(divider)
 }
 
 // WriteByte writes a byte of data to the UART.
-func (uart UART) WriteByte(c byte) error {
+func (uart *UART) WriteByte(c byte) error {
-	uart.Bus.DR.Set(uint32(c))
+	uart.txReg.Set(uint32(c))
 
-	for !uart.Bus.SR.HasBits(stm32.USART_SR_TXE) {
+	for !uart.statusReg.HasBits(uart.txEmptyFlag) {
 	}
 	return nil
 }

src/machine/machine_stm32f103.go

@@ -6,7 +6,6 @@ package machine
 
 import (
 	"device/stm32"
-	"runtime/interrupt"
 	"unsafe"
 )
 
@@ -103,17 +102,10 @@ func enableAltFuncClock(bus unsafe.Pointer) {
 	}
 }
 
-//---------- UART related types and code
+//---------- UART related code
-
-// UART representation
-type UART struct {
-	Buffer    *RingBuffer
-	Bus       *stm32.USART_Type
-	Interrupt interrupt.Interrupt
-}
 
 // Configure the TX and RX pins
-func (uart UART) configurePins(config UARTConfig) {
+func (uart *UART) configurePins(config UARTConfig) {
 
 	// pins
 	switch config.TX {
@@ -133,7 +125,7 @@ func (uart UART) configurePins(config UARTConfig) {
 }
 
 // Determine the divisor for USARTs to get the given baudrate
-func (uart UART) getBaudRateDivisor(br uint32) uint32 {
+func (uart *UART) getBaudRateDivisor(br uint32) uint32 {
 
 	// Note: PCLK2 (from APB2) used for USART1 and PCLK1 for USART2, 3, 4, 5
 	var divider uint32
@@ -147,6 +139,14 @@ func (uart UART) getBaudRateDivisor(br uint32) uint32 {
 	return divider
 }
 
+// Register names vary by ST processor, these are for STM F103xx
+func (uart *UART) setRegisters() {
+	uart.rxReg = &uart.Bus.DR
+	uart.txReg = &uart.Bus.DR
+	uart.statusReg = &uart.Bus.SR
+	uart.txEmptyFlag = stm32.USART_SR_TXE
+}
+
 //---------- SPI related types and code
 
 type SPI struct {

src/machine/machine_stm32f405.go

@@ -7,7 +7,6 @@ package machine
 import (
 	"device/stm32"
 	"math/bits"
-	"runtime/interrupt"
 )
 
 func CPUFrequency() uint32 {
@@ -36,20 +35,13 @@ const (
 
 // -- UART ---------------------------------------------------------------------
 
-type UART struct {
+func (uart *UART) configurePins(config UARTConfig) {
-	Buffer          *RingBuffer
-	Bus             *stm32.USART_Type
-	Interrupt       interrupt.Interrupt
-	AltFuncSelector uint8
-}
-
-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)
 }
 
-func (uart UART) getBaudRateDivisor(baudRate uint32) uint32 {
+func (uart *UART) getBaudRateDivisor(baudRate uint32) uint32 {
 	var clock uint32
 	switch uart.Bus {
 	case stm32.USART1, stm32.USART6:
@@ -60,6 +52,14 @@ func (uart UART) getBaudRateDivisor(baudRate uint32) uint32 {
 	return clock / baudRate
 }
 
+// Register names vary by ST processor, these are for STM F405
+func (uart *UART) setRegisters() {
+	uart.rxReg = &uart.Bus.DR
+	uart.txReg = &uart.Bus.DR
+	uart.statusReg = &uart.Bus.SR
+	uart.txEmptyFlag = stm32.USART_SR_TXE
+}
+
 // -- SPI ----------------------------------------------------------------------
 
 type SPI struct {

src/machine/machine_stm32f407.go

@@ -6,7 +6,6 @@ package machine
 
 import (
 	"device/stm32"
-	"runtime/interrupt"
 )
 
 func CPUFrequency() uint32 {
@@ -33,18 +32,10 @@ const (
 	AF15_EVENTOUT             = 15
 )
 
-//---------- UART related types and code
+//---------- UART related code
-
-// UART representation
-type UART struct {
-	Buffer          *RingBuffer
-	Bus             *stm32.USART_Type
-	Interrupt       interrupt.Interrupt
-	AltFuncSelector uint8
-}
 
 // Configure the UART.
-func (uart UART) configurePins(config UARTConfig) {
+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)
@@ -52,7 +43,7 @@ func (uart UART) configurePins(config UARTConfig) {
 
 // UART baudrate calc based on the bus and clockspeed
 // NOTE: keep this in sync with the runtime/runtime_stm32f407.go clock init code
-func (uart UART) getBaudRateDivisor(baudRate uint32) uint32 {
+func (uart *UART) getBaudRateDivisor(baudRate uint32) uint32 {
 	var clock uint32
 	switch uart.Bus {
 	case stm32.USART1, stm32.USART6:
@@ -63,6 +54,14 @@ func (uart UART) getBaudRateDivisor(baudRate uint32) uint32 {
 	return clock / baudRate
 }
 
+// Register names vary by ST processor, these are for STM F407
+func (uart *UART) setRegisters() {
+	uart.rxReg = &uart.Bus.DR
+	uart.txReg = &uart.Bus.DR
+	uart.statusReg = &uart.Bus.SR
+	uart.txEmptyFlag = stm32.USART_SR_TXE
+}
+
 //---------- SPI related types and code
 
 // SPI on the STM32Fxxx using MODER / alternate function pins

src/machine/machine_stm32f7x2.go

@@ -6,25 +6,16 @@ package machine
 
 import (
 	"device/stm32"
-	"runtime/interrupt"
 )
 
 func CPUFrequency() uint32 {
 	return 216000000
 }
 
-//---------- UART related types and code
+//---------- UART related code
-
-// UART representation
-type UART struct {
-	Buffer          *RingBuffer
-	Bus             *stm32.USART_Type
-	Interrupt       interrupt.Interrupt
-	AltFuncSelector uint8
-}
 
 // Configure the UART.
-func (uart UART) configurePins(config UARTConfig) {
+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)
@@ -32,7 +23,7 @@ func (uart UART) configurePins(config UARTConfig) {
 
 // UART baudrate calc based on the bus and clockspeed
 // NOTE: keep this in sync with the runtime/runtime_stm32f7x2.go clock init code
-func (uart UART) getBaudRateDivisor(baudRate uint32) uint32 {
+func (uart *UART) getBaudRateDivisor(baudRate uint32) uint32 {
 	var clock uint32
 	switch uart.Bus {
 	case stm32.USART1, stm32.USART6:
@@ -42,3 +33,11 @@ func (uart UART) getBaudRateDivisor(baudRate uint32) uint32 {
 	}
 	return clock / baudRate
 }
+
+// Register names vary by ST processor, these are for STM F7x2
+func (uart *UART) setRegisters() {
+	uart.rxReg = &uart.Bus.RDR
+	uart.txReg = &uart.Bus.TDR
+	uart.statusReg = &uart.Bus.ISR
+	uart.txEmptyFlag = stm32.USART_ISR_TXE
+}

src/machine/machine_stm32l5x2.go

@@ -6,25 +6,16 @@ package machine
 
 import (
 	"device/stm32"
-	"runtime/interrupt"
 )
 
 func CPUFrequency() uint32 {
 	return 110000000
 }
 
-//---------- UART related types and code
+//---------- UART related 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) {
+func (uart *UART) configurePins(config UARTConfig) {
 	if config.RX.getPort() == stm32.GPIOG || config.TX.getPort() == stm32.GPIOG {
 		// Enable VDDIO2 power supply, which is an independant power supply for the PGx pins
 		stm32.PWR.CR2.SetBits(stm32.PWR_CR2_IOSV)
@@ -37,6 +28,14 @@ func (uart UART) configurePins(config UARTConfig) {
 
 // UART baudrate calc based on the bus and clockspeed
 // NOTE: keep this in sync with the runtime/runtime_stm32l5x2.go clock init code
-func (uart UART) getBaudRateDivisor(baudRate uint32) uint32 {
+func (uart *UART) getBaudRateDivisor(baudRate uint32) uint32 {
 	return 256 * (CPUFrequency() / baudRate)
 }
+
+// Register names vary by ST processor, these are for STM L5
+func (uart *UART) setRegisters() {
+	uart.rxReg = &uart.Bus.RDR
+	uart.txReg = &uart.Bus.TDR
+	uart.statusReg = &uart.Bus.ISR
+	uart.txEmptyFlag = stm32.USART_ISR_TXE
+}