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// +build stm32,stm32f407
package machine
// Peripheral abstraction layer for the stm32f4(07)
import (
"device/stm32"
"runtime/interrupt"
"unsafe"
)
func CPUFrequency() uint32 {
return 168000000
}
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 5:
return stm32.GPIOF
case 6:
return stm32.GPIOG
case 7:
return stm32.GPIOH
case 8:
return stm32.GPIOI
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.AHB1ENR.SetBits(stm32.RCC_AHB1ENR_GPIOAEN)
case 1:
stm32.RCC.AHB1ENR.SetBits(stm32.RCC_AHB1ENR_GPIOBEN)
case 2:
stm32.RCC.AHB1ENR.SetBits(stm32.RCC_AHB1ENR_GPIOCEN)
case 3:
stm32.RCC.AHB1ENR.SetBits(stm32.RCC_AHB1ENR_GPIODEN)
case 4:
stm32.RCC.AHB1ENR.SetBits(stm32.RCC_AHB1ENR_GPIOEEN)
case 5:
stm32.RCC.AHB1ENR.SetBits(stm32.RCC_AHB1ENR_GPIOFEN)
case 6:
stm32.RCC.AHB1ENR.SetBits(stm32.RCC_AHB1ENR_GPIOGEN)
case 7:
stm32.RCC.AHB1ENR.SetBits(stm32.RCC_AHB1ENR_GPIOHEN)
case 8:
stm32.RCC.AHB1ENR.SetBits(stm32.RCC_AHB1ENR_GPIOIEN)
default:
panic("machine: unknown port")
}
}
// Enable peripheral clock
func enableAltFuncClock(bus unsafe.Pointer) {
switch bus {
case unsafe.Pointer(stm32.USART1):
stm32.RCC.APB2ENR.SetBits(stm32.RCC_APB2ENR_USART1EN)
case unsafe.Pointer(stm32.USART2):
stm32.RCC.APB1ENR.SetBits(stm32.RCC_APB1ENR_USART2EN)
case unsafe.Pointer(stm32.I2C1):
stm32.RCC.APB1ENR.SetBits(stm32.RCC_APB1ENR_I2C1EN)
case unsafe.Pointer(stm32.SPI1):
stm32.RCC.APB2ENR.SetBits(stm32.RCC_APB2ENR_SPI1EN)
}
}
// UART
type UART struct {
Buffer *RingBuffer
Bus *stm32.USART_Type
AltFuncSelector stm32.AltFunc
}
var (
UART0 = UART{
Buffer: NewRingBuffer(),
Bus: stm32.USART2,
AltFuncSelector: stm32.AF7_USART1_2_3,
}
UART1 = &UART0
)
// 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))
// use standard TX/RX pins PA2 and PA3
config.TX.ConfigureAltFunc(PinConfig{Mode: PinModeUARTTX}, uart.AltFuncSelector)
config.RX.ConfigureAltFunc(PinConfig{Mode: PinModeUARTRX}, uart.AltFuncSelector)
/*
Set baud rate(115200)
OVER8 = 0, APB1 = 42mhz
+----------+--------+
| baudrate | BRR |
+----------+--------+
| 1200 | 0x88B8 |
| 2400 | 0x445C |
| 9600 | 0x1117 |
| 19200 | 0x88C |
| 38400 | 0x446 |
| 57600 | 0x2D9 |
| 115200 | 0x16D |
+----------+--------+
*/
uart.Bus.BRR.Set(0x16c)
// Enable USART2 port.
uart.Bus.CR1.Set(stm32.USART_CR1_TE | stm32.USART_CR1_RE | stm32.USART_CR1_RXNEIE | stm32.USART_CR1_UE)
// Enable RX IRQ. TODO: pick the right IRQ_xxx for the bus and the uart
intr := interrupt.New(stm32.IRQ_USART2, func(interrupt.Interrupt) {
UART1.Receive(byte((UART1.Bus.DR.Get() & 0xFF)))
})
intr.SetPriority(0xc0)
intr.Enable()
}
// WriteByte writes a byte of data to the UART.
func (uart UART) WriteByte(c byte) error {
uart.Bus.DR.Set(uint32(c))
for !uart.Bus.SR.HasBits(stm32.USART_SR_TXE) {
}
return nil
}
|
