machine/samd21: implement SPI interface for currently supported SAMD21 boards
Signed-off-by: Ron Evans <ron@hybridgroup.com>
Этот коммит содержится в:
Ron Evans
Ayke
родитель
ea3d232c84
коммит
665c3bdaa6
4 изменённых файлов: 154 добавлений и 15 удалений
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@ -53,13 +53,13 @@ const (
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PROXIMITY = A10
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)
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// USBCDC pins
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// USBCDC pins (logical UART0)
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const (
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USBCDC_DM_PIN = PA24
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USBCDC_DP_PIN = PA25
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)
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// UART0 pins
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// UART0 pins (logical UART1)
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const (
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UART_TX_PIN = PB08 // PORTB
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UART_RX_PIN = PB09 // PORTB
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@ -67,8 +67,11 @@ const (
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// I2C pins
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const (
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SDA_PIN = PA00 // SDA: SERCOM3/PAD[0]
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SCL_PIN = PA01 // SCL: SERCOM3/PAD[1]
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SDA_PIN = PB02 // I2C0 external
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SCL_PIN = PB03 // I2C0 external
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SDA1_PIN = PA00 // I2C1 internal
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SCL1_PIN = PA01 // I2C1 internal
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)
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// I2C on the Circuit Playground Express.
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@ -76,3 +79,15 @@ var (
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I2C0 = I2C{Bus: sam.SERCOM5_I2CM} // external device
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I2C1 = I2C{Bus: sam.SERCOM1_I2CM} // internal device
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)
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// SPI pins (internal flash)
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const (
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SPI0_SCK_PIN = PA21 // SCK: SERCOM3/PAD[3]
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SPI0_MOSI_PIN = PA20 // MOSI: SERCOM3/PAD[2]
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SPI0_MISO_PIN = PA16 // MISO: SERCOM3/PAD[0]
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)
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// SPI on the Circuit Playground Express.
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var (
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SPI0 = SPI{Bus: sam.SERCOM3_SPI}
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)
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@ -58,3 +58,15 @@ const (
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var (
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I2C0 = I2C{Bus: sam.SERCOM3_I2CM}
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)
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// SPI pins
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const (
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SPI0_SCK_PIN = PB11 // SCK: SERCOM4/PAD[3]
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SPI0_MOSI_PIN = PB10 // MOSI: SERCOM4/PAD[2]
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SPI0_MISO_PIN = PA12 // MISO: SERCOM4/PAD[0]
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)
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// SPI on the ItsyBitsy M0.
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var (
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SPI0 = SPI{Bus: sam.SERCOM4_SPI}
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)
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@ -163,6 +163,19 @@ func (p GPIO) Configure(config GPIOConfig) {
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// enable port config
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p.setPinCfg(sam.PORT_PINCFG0_PMUXEN | sam.PORT_PINCFG0_DRVSTR | sam.PORT_PINCFG0_INEN)
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case GPIO_SERCOM_ALT:
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if p.Pin&1 > 0 {
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// odd pin, so save the even pins
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val := p.getPMux() & sam.PORT_PMUX0_PMUXE_Msk
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p.setPMux(val | (GPIO_SERCOM_ALT << sam.PORT_PMUX0_PMUXO_Pos))
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} else {
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// even pin, so save the odd pins
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val := p.getPMux() & sam.PORT_PMUX0_PMUXO_Msk
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p.setPMux(val | (GPIO_SERCOM_ALT << sam.PORT_PMUX0_PMUXE_Pos))
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}
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// enable port config
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p.setPinCfg(sam.PORT_PINCFG0_PMUXEN | sam.PORT_PINCFG0_DRVSTR)
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case GPIO_COM:
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if p.Pin&1 > 0 {
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// odd pin, so save the even pins
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@ -257,9 +270,6 @@ var (
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// The first hardware serial port on the SAMD21. Uses the SERCOM0 interface.
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UART1 = UART{Bus: sam.SERCOM0_USART, Buffer: NewRingBuffer()}
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// The second hardware serial port on the SAMD21. Uses the SERCOM1 interface.
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UART2 = UART{Bus: sam.SERCOM1_USART, Buffer: NewRingBuffer()}
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)
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const (
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@ -272,6 +282,11 @@ const (
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sercomTXPad0 = 0 // Only for UART
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sercomTXPad2 = 1 // Only for UART
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sercomTXPad023 = 2 // Only for UART with TX on PAD0, RTS on PAD2 and CTS on PAD3
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spiTXPad0SCK1 = 0
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spiTXPad2SCK3 = 1
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spiTXPad3SCK1 = 2
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spiTXPad0SCK3 = 3
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)
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// Configure the UART.
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@ -408,13 +423,6 @@ func handleUART1() {
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UART1.Bus.INTFLAG |= sam.SERCOM_USART_INTFLAG_RXC
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}
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//go:export SERCOM1_IRQHandler
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func handleUART2() {
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// should reset IRQ
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UART2.Receive(byte((UART2.Bus.DATA & 0xFF)))
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UART2.Bus.INTFLAG |= sam.SERCOM_USART_INTFLAG_RXC
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}
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// I2C on the SAMD21.
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type I2C struct {
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Bus *sam.SERCOM_I2CM_Type
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@ -644,6 +652,110 @@ func (i2c I2C) readByte() byte {
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return byte(i2c.Bus.DATA)
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}
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// SPI
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type SPI struct {
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Bus *sam.SERCOM_SPI_Type
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}
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// SPIConfig is used to store config info for SPI.
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type SPIConfig struct {
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Frequency uint32
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SCK uint8
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MOSI uint8
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MISO uint8
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LSBFirst bool
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Mode uint8
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}
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// Configure is intended to setup the SPI interface.
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func (spi SPI) Configure(config SPIConfig) {
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config.SCK = SPI0_SCK_PIN
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config.MOSI = SPI0_MOSI_PIN
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config.MISO = SPI0_MISO_PIN
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doPad := spiTXPad2SCK3
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diPad := sercomRXPad0
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// set default frequency
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if config.Frequency == 0 {
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config.Frequency = 4000000
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}
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// Disable SPI port.
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spi.Bus.CTRLA &^= sam.SERCOM_SPI_CTRLA_ENABLE
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for (spi.Bus.SYNCBUSY & sam.SERCOM_SPI_SYNCBUSY_ENABLE) > 0 {
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}
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// enable pins
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GPIO{config.SCK}.Configure(GPIOConfig{Mode: GPIO_SERCOM_ALT})
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GPIO{config.MOSI}.Configure(GPIOConfig{Mode: GPIO_SERCOM_ALT})
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GPIO{config.MISO}.Configure(GPIOConfig{Mode: GPIO_SERCOM_ALT})
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// reset SERCOM
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spi.Bus.CTRLA |= sam.SERCOM_SPI_CTRLA_SWRST
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for (spi.Bus.CTRLA&sam.SERCOM_SPI_CTRLA_SWRST) > 0 ||
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(spi.Bus.SYNCBUSY&sam.SERCOM_SPI_SYNCBUSY_SWRST) > 0 {
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}
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// set bit transfer order
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dataOrder := 0
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if config.LSBFirst {
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dataOrder = 1
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}
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// Set SPI master
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spi.Bus.CTRLA = (sam.SERCOM_SPI_CTRLA_MODE_SPI_MASTER << sam.SERCOM_SPI_CTRLA_MODE_Pos) |
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sam.RegValue(doPad<<sam.SERCOM_SPI_CTRLA_DOPO_Pos) |
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sam.RegValue(diPad<<sam.SERCOM_SPI_CTRLA_DIPO_Pos) |
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sam.RegValue(dataOrder<<sam.SERCOM_SPI_CTRLA_DORD_Pos)
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spi.Bus.CTRLB |= (0 << sam.SERCOM_SPI_CTRLB_CHSIZE_Pos) | // 8bit char size
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sam.SERCOM_SPI_CTRLB_RXEN // receive enable
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for (spi.Bus.SYNCBUSY & sam.SERCOM_SPI_SYNCBUSY_CTRLB) > 0 {
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}
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// set mode
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switch config.Mode {
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case 0:
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spi.Bus.CTRLA &^= sam.SERCOM_SPI_CTRLA_CPHA
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spi.Bus.CTRLA &^= sam.SERCOM_SPI_CTRLA_CPOL
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case 1:
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spi.Bus.CTRLA |= sam.SERCOM_SPI_CTRLA_CPHA
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spi.Bus.CTRLA &^= sam.SERCOM_SPI_CTRLA_CPOL
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case 2:
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spi.Bus.CTRLA &^= sam.SERCOM_SPI_CTRLA_CPHA
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spi.Bus.CTRLA |= sam.SERCOM_SPI_CTRLA_CPOL
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case 3:
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spi.Bus.CTRLA |= sam.SERCOM_SPI_CTRLA_CPHA | sam.SERCOM_SPI_CTRLA_CPOL
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default: // to mode 0
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spi.Bus.CTRLA &^= sam.SERCOM_SPI_CTRLA_CPHA
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spi.Bus.CTRLA &^= sam.SERCOM_SPI_CTRLA_CPOL
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}
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// Set synch speed for SPI
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baudRate := (CPU_FREQUENCY / (2 * config.Frequency)) - 1
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spi.Bus.BAUD = sam.RegValue8(baudRate)
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// Enable SPI port.
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spi.Bus.CTRLA |= sam.SERCOM_SPI_CTRLA_ENABLE
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for (spi.Bus.SYNCBUSY & sam.SERCOM_SPI_SYNCBUSY_ENABLE) > 0 {
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}
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}
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// Transfer writes/reads a single byte using the SPI interface.
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func (spi SPI) Transfer(w byte) (byte, error) {
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// write data
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spi.Bus.DATA = sam.RegValue(w)
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// wait for receive
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for (spi.Bus.INTFLAG & sam.SERCOM_SPI_INTFLAG_RXC) == 0 {
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}
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// return data
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return byte(spi.Bus.DATA), nil
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}
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// PWM
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const period = 0xFFFF
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@ -1,4 +1,4 @@
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// +build nrf stm32f103xx
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// +build nrf stm32f103xx atsamd21g18a
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package machine
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