machine

package
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 Go to latest Published: Aug 28, 2025 License: Apache-2.0 Imports: 4 Imported by: 0

Documentation

Index

Constants

View Source 
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.

Deprecated: use 100 * machine.KHz or 400 * machine.KHz instead.

View Source 
const (
	KHz = 1000
	MHz = 1000_000
	GHz = 1000_000_000
)

Generic constants.

View Source 
const (
	Mode0 = 0
	Mode1 = 1
	Mode2 = 2
	Mode3 = 3
)

SPI phase and polarity configs CPOL and CPHA

View Source 
const Device = deviceName

Device is the running program's chip name, such as "ATSAMD51J19A" or "nrf52840". It is not the same as the CPU name.

The constant is some hardcoded default value if the program does not target a particular chip but instead runs in WebAssembly for example.

View Source 
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).

Variables

View Source 
var (
	ErrTimeoutRNG         = errors.New("machine: RNG Timeout")
	ErrClockRNG           = errors.New("machine: RNG Clock Error")
	ErrSeedRNG            = errors.New("machine: RNG Seed Error")
	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")
)
View Source 
var (
	UART0 = hardwareUART0
	UART1 = hardwareUART1
	SPI0  = &SPI{0}
	SPI1  = &SPI{1}
	I2C0  = &I2C{0}
)
View Source 
var (
	ErrPWMPeriodTooLong = errors.New("pwm: period too long")
)
View Source 
var (
	ErrTxInvalidSliceSize = errors.New("SPI write and read slices must be same size")
)
View Source 
var Serial = hardwareUART0

The Serial port always points to the default UART in a simulated environment.

TODO: perhaps this should be a special serial object that outputs via WASI stdout calls.

View Source 
var (
	USB = &UART{100}
)

Functions

func GetRNG 

func GetRNG() (uint32, error)

GetRNG returns 32 bits of random data from the WASI random source.

func InitADC 

func InitADC()

InitADC enables support for ADC peripherals.

Types

type ADC 

type ADC struct {
	Pin Pin
}

func (ADC) Configure 

func (adc ADC) Configure(ADCConfig)

Configure configures an ADC pin to be able to be used to read data.

func (ADC) Get 

func (adc ADC) Get() uint16

Get reads the current analog value from this ADC peripheral.

type ADCConfig 

type ADCConfig struct {
	Reference  uint32 // analog reference voltage (AREF) in millivolts
	Resolution uint32 // number of bits for a single conversion (e.g., 8, 10, 12)
	Samples    uint32 // number of samples for a single conversion (e.g., 4, 8, 16, 32)
	SampleTime uint32 // sample time, in microseconds (µs)
}

ADCConfig holds ADC configuration parameters. If left unspecified, the zero value of each parameter will use the peripheral's default settings.

type I2C 

type I2C struct {
	Bus uint8
}

I2C is a generic implementation of the Inter-IC communication protocol.

func (*I2C) Configure 

func (i2c *I2C) Configure(config I2CConfig) error

Configure is intended to setup the I2C interface.

func (*I2C) ReadRegister 

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) SetBaudRate 

func (i2c *I2C) SetBaudRate(br uint32) error

SetBaudRate sets the I2C frequency.

func (*I2C) Tx 

func (i2c *I2C) Tx(addr uint16, w, r []byte) error

Tx does a single I2C transaction at the specified address.

func (*I2C) WriteRegister 

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 

type I2CConfig struct {
	Frequency uint32
	SCL       Pin
	SDA       Pin
}

I2CConfig is used to store config info for I2C.

type I2CMode 

type I2CMode int

I2CMode determines if an I2C peripheral is in Controller or Target mode. 

const (
	// I2CModeController represents an I2C peripheral in controller mode.
	I2CModeController I2CMode = iota

	// I2CModeTarget represents an I2C peripheral in target mode.
	I2CModeTarget
)

type I2CTargetEvent 

type I2CTargetEvent uint8

I2CTargetEvent reflects events on the I2C bus 

const (
	// I2CReceive indicates target has received a message from the controller.
	I2CReceive I2CTargetEvent = iota

	// I2CRequest indicates the controller is expecting a message from the target.
	I2CRequest

	// I2CFinish indicates the controller has ended the transaction.
	//
	// I2C controllers can chain multiple receive/request messages without
	// relinquishing the bus by doing 'restarts'.  I2CFinish indicates the
	// bus has been relinquished by an I2C 'stop'.
	I2CFinish
)

type NullSerial 

type NullSerial struct {
}

NullSerial is a serial version of /dev/null (or null router): it drops everything that is written to it.

func (NullSerial) Buffered 

func (ns NullSerial) Buffered() int

Buffered returns how many bytes are buffered in the UART. It always returns 0 as there are no bytes to read.

func (NullSerial) Configure 

func (ns NullSerial) Configure(config UARTConfig) error

Configure does nothing: the null serial has no configuration.

func (NullSerial) ReadByte 

func (ns NullSerial) ReadByte() (byte, error)

ReadByte always returns an error because there aren't any bytes to read.

func (NullSerial) Write 

func (ns NullSerial) Write(p []byte) (n int, err error)

Write is a no-op: none of the data is being written and it will not return an error.

func (NullSerial) WriteByte 

func (ns NullSerial) WriteByte(b byte) error

WriteByte is a no-op: the null serial doesn't write bytes.

type PDMConfig 

type PDMConfig struct {
	Stereo bool
	DIN    Pin
	CLK    Pin
}

type PWMConfig 

type PWMConfig struct {
	// PWM period in nanosecond. Leaving this zero will pick a reasonable period
	// value for use with LEDs.
	// If you want to configure a frequency instead of a period, you can use the
	// following formula to calculate a period from a frequency:
	//
	//     period = 1e9 / frequency
	//
	Period uint64
}

PWMConfig allows setting some configuration while configuring a PWM peripheral. A zero PWMConfig is ready to use for simple applications such as dimming LEDs.

type 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 (Pin) Configure 

func (p Pin) Configure(config PinConfig)

func (Pin) Get 

func (p Pin) Get() bool

func (Pin) High 

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 (Pin) Low 

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 (Pin) Set 

func (p Pin) Set(value bool)

type PinConfig 

type PinConfig struct {
	Mode PinMode
}

type PinMode 

type PinMode uint8

PinMode sets the direction and pull mode of the pin. For example, PinOutput sets the pin as an output and PinInputPullup sets the pin as an input with a pull-up. 

const (
	PinInput PinMode = iota
	PinOutput
	PinInputPullup
	PinInputPulldown
)

type RingBuffer 

type RingBuffer struct {
	// contains filtered or unexported fields
}

RingBuffer is ring buffer implementation inspired by post at https://www.embeddedrelated.com/showthread/comp.arch.embedded/77084-1.php

func NewRingBuffer 

func NewRingBuffer() *RingBuffer

NewRingBuffer returns a new ring buffer.

func (*RingBuffer) Clear 

func (rb *RingBuffer) Clear()

Clear resets the head and tail pointer to zero.

func (*RingBuffer) Get 

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 (*RingBuffer) Put 

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 (*RingBuffer) Used 

func (rb *RingBuffer) Used() uint8

Used returns how many bytes in buffer have been used.

type SPI 

type SPI struct {
	Bus uint8
}

func (*SPI) Configure 

func (spi *SPI) Configure(config SPIConfig) error

func (*SPI) Transfer 

func (spi *SPI) Transfer(w byte) (byte, error)

Transfer writes/reads a single byte using the SPI interface.

func (*SPI) Tx 

func (spi *SPI) Tx(w, r []byte) error

Tx handles read/write operation for SPI interface. Since SPI is a synchronous 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 

type SPIConfig struct {
	Frequency uint32
	SCK       Pin
	SDO       Pin
	SDI       Pin
	Mode      uint8
}

type UART 

type UART struct {
	Bus uint8
}

func (*UART) Buffered 

func (uart *UART) Buffered() int

Buffered returns the number of bytes currently stored in the RX buffer.

func (*UART) Configure 

func (uart *UART) Configure(config UARTConfig)

Configure the UART.

func (*UART) Read 

func (uart *UART) Read(data []byte) (n int, err error)

Read from the UART.

func (*UART) ReadByte 

func (uart *UART) ReadByte() (byte, error)

ReadByte reads a single byte from the UART.

func (*UART) Write 

func (uart *UART) Write(data []byte) (n int, err error)

Write to the UART.

func (*UART) WriteByte 

func (uart *UART) WriteByte(b byte) error

WriteByte writes a single byte to the UART.

type UARTConfig 

type UARTConfig struct {
	BaudRate uint32
	TX       Pin
	RX       Pin
	RTS      Pin
	CTS      Pin
}

UARTConfig is a struct with which a UART (or similar object) can be configured. The baud rate is usually respected, but TX and RX may be ignored depending on the chip and the type of object.

Source Files

View all Source files

Directories

Path Synopsis
package usb contains the subpackages with USB descriptors and device implementations for standard USB device classes such as the Communcation Data Class (CDC), Human Interface Device (HID), and Audio Device Class (ADC).
 package usb contains the subpackages with USB descriptors and device implementations for standard USB device classes such as the Communcation Data Class (CDC), Human Interface Device (HID), and Audio Device Class (ADC).
adc
package adc is for USB Audio Device Class devices.
 package adc is for USB Audio Device Class devices.
adc/midi
cdc
package cdc is for USB Communication Device Class devices.
 package cdc is for USB Communication Device Class devices.
descriptor
package descriptor is for the USB descriptor definitions.
 package descriptor is for the USB descriptor definitions.
hid
package hid is for USB Human Interface Devices.
 package hid is for USB Human Interface Devices.
hid/joystick
hid/keyboard
hid/mouse
msc
msc/csw
msc/scsi

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