stm32: Harmonization of UART logic

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 representation
-type UART struct {
-	Buffer          *RingBuffer
-	Bus             *stm32.USART_Type
-	Interrupt       interrupt.Interrupt
-	AltFuncSelector uint8
-}
+//---------- UART related code
 
 // 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