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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 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
// NOTE: keep this in sync with the runtime/runtime_stm32f407.go clock init code
func (uart UART) getBaudRateDivisor(baudRate uint32) uint32 {
var clock uint32
switch uart.Bus {
case stm32.USART1, stm32.USART6:
clock = CPUFrequency() / 2 // APB2 Frequency
case stm32.USART2, stm32.USART3, stm32.UART4, stm32.UART5:
clock = CPUFrequency() / 4 // APB1 Frequency
}
return clock / baudRate
}
//---------- 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
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 true {
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.MOSI.ConfigureAltFunc(PinConfig{Mode: PinModeSPIMOSI}, spi.AltFuncSelector)
config.MISO.ConfigureAltFunc(PinConfig{Mode: PinModeSPIMISO}, spi.AltFuncSelector)
}
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