const (
P00 Pin = 0
P01 Pin = 1
P02 Pin = 2
P03 Pin = 3
P04 Pin = 4
P05 Pin = 5
P06 Pin = 6
P07 Pin = 7
P08 Pin = 8
P09 Pin = 9
P10 Pin = 10
P11 Pin = 11
P12 Pin = 12
P13 Pin = 13
P14 Pin = 14
P15 Pin = 15
P16 Pin = 16
P17 Pin = 17
P18 Pin = 18
P19 Pin = 19
P20 Pin = 20
P21 Pin = 21
P22 Pin = 22
P23 Pin = 23
P24 Pin = 24
P25 Pin = 25
P26 Pin = 26
P27 Pin = 27
P28 Pin = 28
P29 Pin = 29
P30 Pin = 30
P31 Pin = 31
)
const (
D0 = P16
D1 = P17
D2 = P18
D3 = P19 // Green LED/PWM (PWM1_PWM1)
D4 = P20 // PWM (PWM1_PWM0)
D5 = P21 // Blue LED/PWM (PWM1_PWM2)
D6 = P22 // Red LED/PWM (PWM1_PWM3)
D7 = P16
D8 = NoPin // PWM?
D9 = P01
D10 = P02 // SPI1_CS0
D11 = P03 // SPI1_DQ0
D12 = P04 // SPI1_DQ1
D13 = P05 // SPI1_SCK
D14 = NoPin // not connected
D15 = P09 // does not seem to work?
D16 = P10 // PWM (PWM2_PWM0)
D17 = P11 // PWM (PWM2_PWM1)
D18 = P12 // SDA (I2C0_SDA)/PWM (PWM2_PWM2)
D19 = P13 // SDL (I2C0_SCL)/PWM (PWM2_PWM3)
)
const (
LED = LED1
LED1 = LED_RED
LED2 = LED_GREEN
LED3 = LED_BLUE
LED_RED = P22
LED_GREEN = P19
LED_BLUE = P21
)
const (
// TODO: figure out the pin numbers for these.
UART_TX_PIN = D1
UART_RX_PIN = D0
)
const (
SPI0_SCK_PIN = NoPin
SPI0_SDO_PIN = NoPin
SPI0_SDI_PIN = NoPin
SPI1_SCK_PIN = D13
SPI1_SDO_PIN = D11
SPI1_SDI_PIN = D12
)
SPI pins
const (
I2C0_SDA_PIN = D18
I2C0_SCL_PIN = D19
)
I2C pins
const (
TWI_FREQ_100KHZ = 100000
TWI_FREQ_400KHZ = 400000
)
TWI_FREQ is the I2C bus speed. Normally either 100 kHz, or 400 kHz for high-speed bus.
const NoPin = Pin(0xff)
NoPin explicitly indicates “not a pin”. Use this pin if you want to leave one of the pins in a peripheral unconfigured (if supported by the hardware).
const (
PinInput PinMode = iota
PinOutput
PinPWM
PinSPI
PinI2C = PinSPI
)
const (
Mode0 = 0
Mode1 = 1
Mode2 = 2
Mode3 = 3
)
SPI phase and polarity configs CPOL and CPHA
var (
SPI1 = SPI{
Bus: sifive.QSPI1,
}
)
SPI on the HiFive1.
var (
I2C0 = I2C{
Bus: sifive.I2C0,
}
)
I2C on the HiFive1 rev B.
var (
ErrInvalidInputPin = errors.New("machine: invalid input pin")
ErrInvalidOutputPin = errors.New("machine: invalid output pin")
ErrInvalidClockPin = errors.New("machine: invalid clock pin")
ErrInvalidDataPin = errors.New("machine: invalid data pin")
ErrNoPinChangeChannel = errors.New("machine: no channel available for pin interrupt")
)
var (
UART0 = UART{Bus: sifive.UART0, Buffer: NewRingBuffer()}
)
var (
ErrTxInvalidSliceSize = errors.New("SPI write and read slices must be same size")
)
func CPUFrequency() uint32
func NewRingBuffer() *RingBuffer
NewRingBuffer returns a new ring buffer.
type ADC struct {
Pin Pin
}
type I2C struct {
Bus *sifive.I2C_Type
}
I2C on the FE310-G002.
func (i2c I2C) Configure(config I2CConfig) error
Configure is intended to setup the I2C interface.
func (i2c I2C) ReadRegister(address uint8, register uint8, data []byte) error
ReadRegister transmits the register, restarts the connection as a read operation, and reads the response.
Many I2C-compatible devices are organized in terms of registers. This method is a shortcut to easily read such registers. Also, it only works for devices with 7-bit addresses, which is the vast majority.
func (i2c I2C) Tx(addr uint16, w, r []byte) error
Tx does a single I2C transaction at the specified address. It clocks out the given address, writes the bytes in w, reads back len® bytes and stores them in r, and generates a stop condition on the bus.
func (i2c I2C) WriteRegister(address uint8, register uint8, data []byte) error
WriteRegister transmits first the register and then the data to the peripheral device.
Many I2C-compatible devices are organized in terms of registers. This method is a shortcut to easily write to such registers. Also, it only works for devices with 7-bit addresses, which is the vast majority.
type I2CConfig struct {
Frequency uint32
SCL Pin
SDA Pin
}
I2CConfig is used to store config info for I2C.
type PWM struct {
Pin Pin
}
type Pin uint8
Pin is a single pin on a chip, which may be connected to other hardware devices. It can either be used directly as GPIO pin or it can be used in other peripherals like ADC, I2C, etc.
func (p Pin) Configure(config PinConfig)
Configure this pin with the given configuration.
func (p Pin) Get() bool
Get returns the current value of a GPIO pin.
func (p Pin) High()
High sets this GPIO pin to high, assuming it has been configured as an output pin. It is hardware dependent (and often undefined) what happens if you set a pin to high that is not configured as an output pin.
func (p Pin) Low()
Low sets this GPIO pin to low, assuming it has been configured as an output pin. It is hardware dependent (and often undefined) what happens if you set a pin to low that is not configured as an output pin.
func (p Pin) Set(high bool)
Set the pin to high or low.
type PinConfig struct {
Mode PinMode
}
type PinMode uint8
type RingBuffer struct {
rxbuffer [bufferSize]volatile.Register8
head volatile.Register8
tail volatile.Register8
}
RingBuffer is ring buffer implementation inspired by post at https://www.embeddedrelated.com/showthread/comp.arch.embedded/77084-1.php
func (rb *RingBuffer) Clear()
Clear resets the head and tail pointer to zero.
func (rb *RingBuffer) Get() (byte, bool)
Get returns a byte from the buffer. If the buffer is empty, the method will return a false as the second value.
func (rb *RingBuffer) Put(val byte) bool
Put stores a byte in the buffer. If the buffer is already full, the method will return false.
func (rb *RingBuffer) Used() uint8
Used returns how many bytes in buffer have been used.
type SPI struct {
Bus *sifive.QSPI_Type
}
SPI on the FE310. The normal SPI0 is actually a quad-SPI meant for flash, so it is best to use SPI1 or SPI2 port for most applications.
func (spi SPI) Configure(config SPIConfig) error
Configure is intended to setup the SPI interface.
func (spi SPI) Transfer(w byte) (byte, error)
Transfer writes/reads a single byte using the SPI interface.
func (spi SPI) Tx(w, r []byte) error
Tx handles read/write operation for SPI interface. Since SPI is a syncronous write/read interface, there must always be the same number of bytes written as bytes read. The Tx method knows about this, and offers a few different ways of calling it.
This form sends the bytes in tx buffer, putting the resulting bytes read into the rx buffer. Note that the tx and rx buffers must be the same size:
spi.Tx(tx, rx)
This form sends the tx buffer, ignoring the result. Useful for sending “commands” that return zeros until all the bytes in the command packet have been received:
spi.Tx(tx, nil)
This form sends zeros, putting the result into the rx buffer. Good for reading a “result packet”:
spi.Tx(nil, rx)
type SPIConfig struct {
Frequency uint32
SCK Pin
SDO Pin
SDI Pin
LSBFirst bool
Mode uint8
}
SPIConfig is used to store config info for SPI.
type UART struct {
Bus *sifive.UART_Type
Buffer *RingBuffer
}
func (uart UART) Buffered() int
Buffered returns the number of bytes currently stored in the RX buffer.
func (uart UART) Configure(config UARTConfig)
func (uart UART) Read(data []byte) (n int, err error)
Read from the RX buffer.
func (uart UART) ReadByte() (byte, error)
ReadByte reads a single byte from the RX buffer. If there is no data in the buffer, returns an error.
func (uart UART) Receive(data byte)
Receive handles adding data to the UART’s data buffer. Usually called by the IRQ handler for a machine.
func (uart UART) Write(data []byte) (n int, err error)
Write data to the UART.
func (uart UART) WriteByte(c byte)
type UARTConfig struct {
BaudRate uint32
TX Pin
RX Pin
}