const (
D0 = PD0 // RX
D1 = PD1 // TX
D2 = PD2
D3 = PD3
D4 = PD4
D5 = PD5
D6 = PD6
D7 = PD7
D8 = PB0
D9 = PB1
D10 = PB2
D11 = PB3
D12 = PB4
D13 = PB5
)
Digital pins, marked as plain numbers on the board.
const LED Pin = D13
LED on the Arduino
const (
ADC0 Pin = PC0
ADC1 Pin = PC1
ADC2 Pin = PC2
ADC3 Pin = PC3
ADC4 Pin = PC4 // Used by TWI for SDA
ADC5 Pin = PC5 // Used by TWI for SCL
)
ADC on the Arduino
const (
UART_TX_PIN Pin = PD1
UART_RX_PIN Pin = PD0
)
UART pins
const (
PB0 = portB + 0
PB1 = portB + 1
PB2 = portB + 2
PB3 = portB + 3
PB4 = portB + 4
PB5 = portB + 5
PB6 = portB + 6
PB7 = portB + 7
PC0 = portC + 0
PC1 = portC + 1
PC2 = portC + 2
PC3 = portC + 3
PC4 = portC + 4
PC5 = portC + 5
PC6 = portC + 6
PC7 = portC + 7
PD0 = portD + 0
PD1 = portD + 1
PD2 = portD + 2
PD3 = portD + 3
PD4 = portD + 4
PD5 = portD + 5
PD6 = portD + 6
PD7 = portD + 7
)
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
PinInputPullup
PinOutput
)
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 I2C0 = I2C{}
I2C0 is the only I2C interface on most AVRs.
var (
// UART0 is the hardware serial port on the AVR.
UART0 = UART{Buffer: NewRingBuffer()}
)
UART
func CPUFrequency() uint32
Return the current CPU frequency in hertz.
func InitADC()
InitADC initializes the registers needed for ADC.
func InitPWM()
InitPWM initializes the registers needed for PWM.
func NewRingBuffer() *RingBuffer
NewRingBuffer returns a new ring buffer.
type ADC struct {
Pin Pin
}
func (a ADC) Configure()
Configure configures a ADCPin to be able to be used to read data.
func (a ADC) Get() uint16
Get returns the current value of a ADC pin, in the range 0..0xffff. The AVR has an ADC of 10 bits precision so the lower 6 bits will be zero.
type I2C struct {
}
I2C on AVR.
func (i2c I2C) Configure(config I2CConfig)
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
}
I2CConfig is used to store config info for I2C.
type PWM struct {
Pin Pin
}
func (pwm PWM) Configure() error
Configure configures a PWM pin for output.
func (pwm PWM) Set(value uint16)
Set turns on the duty cycle for a PWM pin using the provided value. On the AVR this is normally a 8-bit value ranging from 0 to 255.
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 sets the pin to input or output.
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) PortMaskClear() (*volatile.Register8, uint8)
Return the register and mask to disable a given port. This can be used to implement bit-banged drivers.
Warning: there are no separate pin set/clear registers on the AVR. The returned mask is only valid as long as no other pin in the same port has been changed.
func (p Pin) PortMaskSet() (*volatile.Register8, uint8)
Return the register and mask to enable a given GPIO pin. This can be used to implement bit-banged drivers.
Warning: there are no separate pin set/clear registers on the AVR. The returned mask is only valid as long as no other pin in the same port has been changed.
func (p Pin) Set(value bool)
Set changes the value of the GPIO pin. The pin must be configured as output.
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 UART struct {
Buffer *RingBuffer
}
UART on the AVR.
func (uart UART) Buffered() int
Buffered returns the number of bytes currently stored in the RX buffer.
func (uart UART) Configure(config UARTConfig)
Configure the UART on the AVR. Defaults to 9600 baud on Arduino.
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) error
WriteByte writes a byte of data to the UART.
type UARTConfig struct {
BaudRate uint32
TX Pin
RX Pin
}