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stm32 add SPI for stm32f4

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This commit is contained in:
GeoffThomas
2020-03-22 10:28:47 -05:00
committed by Ron Evans
parent ac73430502
commit b4dddfe439
6 changed files with 217 additions and 93 deletions
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src/machine/machine_stm32f103xx.go
+11 -92
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@@ -148,7 +148,8 @@ func (uart UART) getBaudRateDivisor(br uint32) uint32 {
return divider
}
// SPI on the STM32.
//---------- SPI related types and code
type SPI struct {
Bus *stm32.SPI_Type
}
@@ -161,26 +162,8 @@ var (
SPI0 = SPI1
)
// SPIConfig is used to store config info for SPI.
type SPIConfig struct {
Frequency uint32
SCK Pin
MOSI Pin
MISO Pin
LSBFirst bool
Mode uint8
}
// Configure is intended to setup the STM32 SPI1 interface.
// Features still TODO:
// - support SPI2 and SPI3
// - allow setting data size to 16 bits?
// - allow setting direction in HW for additional optimization?
// - hardware SS pin?
func (spi SPI) Configure(config SPIConfig) {
// enable clock for SPI
stm32.RCC.APB2ENR.SetBits(stm32.RCC_APB2ENR_SPI1EN)
// Set baud rate for SPI
func (spi SPI) getBaudRate(config SPIConfig) uint32 {
var conf uint32
// set frequency dependent on PCLK2 prescaler (div 1)
@@ -203,82 +186,18 @@ func (spi SPI) Configure(config SPIConfig) {
default:
conf |= stm32.SPI_BaudRatePrescaler_256
}
// set bit transfer order
if config.LSBFirst {
conf |= stm32.SPI_FirstBit_LSB
}
// set mode
switch config.Mode {
case 0:
conf &^= (1 << stm32.SPI_CR1_CPOL_Pos)
conf &^= (1 << stm32.SPI_CR1_CPHA_Pos)
case 1:
conf &^= (1 << stm32.SPI_CR1_CPOL_Pos)
conf |= (1 << stm32.SPI_CR1_CPHA_Pos)
case 2:
conf |= (1 << stm32.SPI_CR1_CPOL_Pos)
conf &^= (1 << stm32.SPI_CR1_CPHA_Pos)
case 3:
conf |= (1 << stm32.SPI_CR1_CPOL_Pos)
conf |= (1 << stm32.SPI_CR1_CPHA_Pos)
default: // to mode 0
conf &^= (1 << stm32.SPI_CR1_CPOL_Pos)
conf &^= (1 << stm32.SPI_CR1_CPHA_Pos)
}
// set to SPI master
conf |= stm32.SPI_Mode_Master
// now set the configuration
spi.Bus.CR1.Set(conf)
// init pins
spi.setPins(config.SCK, config.MOSI, config.MISO)
// enable SPI interface
spi.Bus.CR1.SetBits(stm32.SPI_CR1_SPE)
return conf
}
// Transfer writes/reads a single byte using the SPI interface.
func (spi SPI) Transfer(w byte) (byte, error) {
// Write data to be transmitted to the SPI data register
spi.Bus.DR.Set(uint32(w))
// Wait until transmit complete
for !spi.Bus.SR.HasBits(stm32.SPI_SR_TXE) {
}
// Wait until receive complete
for !spi.Bus.SR.HasBits(stm32.SPI_SR_RXNE) {
}
// Wait until SPI is not busy
for spi.Bus.SR.HasBits(stm32.SPI_SR_BSY) {
}
// Return received data from SPI data register
return byte(spi.Bus.DR.Get()), nil
// Configure SPI pins for input output and clock
func (spi SPI) configurePins(config SPIConfig) {
config.SCK.Configure(PinConfig{Mode: PinOutput50MHz + PinOutputModeAltPushPull})
config.MOSI.Configure(PinConfig{Mode: PinOutput50MHz + PinOutputModeAltPushPull})
config.MISO.Configure(PinConfig{Mode: PinInputModeFloating})
}
func (spi SPI) setPins(sck, mosi, miso Pin) {
if sck == 0 {
sck = SPI0_SCK_PIN
}
if mosi == 0 {
mosi = SPI0_MOSI_PIN
}
if miso == 0 {
miso = SPI0_MISO_PIN
}
//---------- I2C related types and code
sck.Configure(PinConfig{Mode: PinOutput50MHz + PinOutputModeAltPushPull})
mosi.Configure(PinConfig{Mode: PinOutput50MHz + PinOutputModeAltPushPull})
miso.Configure(PinConfig{Mode: PinInputModeFloating})
}
// I2C on the STM32F103xx.
type I2C struct {
Bus *stm32.I2C_Type
}