periph: Index | Examples | Files | Directories

package periph

import ""

Package periph is a peripheral I/O library.

Package periph acts as a registry of drivers. It is focused on providing high quality host drivers that provide high-speed access to the hardware on the host computer itself.

To learn more about the goals and design, visit

Every device driver should register itself in its package init() function by calling periph.MustRegister().

User shall call either host.Init() or hostextra.Init() on startup to initialize all the registered drivers.


cmd/ contains executable tools to communicate directly with the devices or the buses.

cmd/ is allowed to import from conn/, devices/ and host/.


conn/ contains interfaces and registries for all the supported protocols and connections (I²C, SPI, GPIO, etc).

conn/ is not allowed to import from any other package.


devices/ contains devices drivers that are connected to bus, port or connection (i.e I²C, SPI, 1-wire, GPIO) that can be controlled by the host, i.e. ssd1306 (display controller), bm280 (environmental sensor), etc.

devices/ is allowed to import from conn/ and host/.


experimental/ contains the drivers that are in the experimental area, not yet considered stable. See for the process to move drivers out of this area.

experimental/ is allowed to import from conn/, devices/ and host/.


host/ contains all the implementations relating to the host itself, the CPU and buses that are exposed by the host onto which devices can be connected, i.e. I²C, SPI, GPIO, etc.

host/ is allowed to import from conn/ only.


// host.Init() registers all the periph-provided host driver automatically,
// so it is preferable to use than periph.Init().
// You can also use for additional drivers
// that depends on cgo and/or third party packages.
state, err := host.Init()
if err != nil {
    log.Fatalf("failed to initialize periph: %v", err)

// Prints the loaded driver.
fmt.Printf("Using drivers:\n")
for _, driver := range state.Loaded {
    fmt.Printf("- %s\n", driver)

// Prints the driver that were skipped as irrelevant on the platform.
fmt.Printf("Drivers skipped:\n")
for _, failure := range state.Skipped {
    fmt.Printf("- %s: %s\n", failure.D, failure.Err)

// Having drivers failing to load may not require process termination. It
// is possible to continue to run in partial failure mode.
fmt.Printf("Drivers failed to load:\n")
for _, failure := range state.Failed {
    fmt.Printf("- %s: %v\n", failure.D, failure.Err)

// Use pins, buses, devices, etc.



Package Files

periph.go periph_parallel.go

func MustRegister Uses

func MustRegister(d Driver)

MustRegister calls Register() and panics if registration fails.

This is the function to call in a driver's package init() function.

func Register Uses

func Register(d Driver) error

Register registers a driver to be initialized automatically on Init().

The d.String() value must be unique across all registered drivers.

It is an error to call Register() after Init() was called.

type Driver Uses

type Driver interface {
    // String returns the name of the driver, as to be presented to the user.
    // It must be unique in the list of registered drivers.
    String() string
    // Prerequisites returns a list of drivers that must be successfully loaded
    // first before attempting to load this driver.
    // A driver listing a prerequisite not registered is a fatal failure at
    // initialization time.
    Prerequisites() []string
    // After returns a list of drivers that must be loaded first before
    // attempting to load this driver.
    // Unlike Prerequisites(), this driver will still be attempted even if the
    // listed driver is missing or failed to load.
    // This permits serialization without hard requirement.
    After() []string
    // Init initializes the driver.
    // A driver may enter one of the three following state: loaded successfully,
    // was skipped as irrelevant on this host, failed to load.
    // On success, it must return true, nil.
    // When irrelevant (skipped), it must return false, errors.New(<reason>).
    // On failure, it must return true, errors.New(<reason>). The failure must
    // state why it failed, for example an expected OS provided driver couldn't
    // be opened, e.g. /dev/gpiomem on Raspbian.
    Init() (bool, error)

Driver is an implementation for a protocol.

type DriverFailure Uses

type DriverFailure struct {
    D   Driver
    Err error

DriverFailure is a driver that wasn't loaded, either because it was skipped or because it failed to load.

func (DriverFailure) String Uses

func (d DriverFailure) String() string

type State Uses

type State struct {
    Loaded  []Driver
    Skipped []DriverFailure
    Failed  []DriverFailure

State is the state of loaded device drivers.

Each list is sorted by the driver name.

func Init Uses

func Init() (*State, error)

Init initialises all the relevant drivers.

Drivers are started concurrently.

It is safe to call this function multiple times, the previous state is returned on later calls.

Users will want to use host.Init(), which guarantees a baseline of included host drivers.


cmdPackage cmd contains tools.
cmd/apa102apa102 writes to a strip of APA102 LED.
cmd/bmxx80bmxx80 reads environmental data from a BMP180/BME280/BMP280.
cmd/cap1xxxcap1xxx sense touches.
cmd/gpio-listgpio-list prints out the function of each GPIO pin.
cmd/gpio-readgpio-read reads a GPIO pin.
cmd/gpio-writegpio-write sets a GPIO pin to low or high.
cmd/headers-listheaders-list prints out the headers as found on the computer and print the functionality of each pin.
cmd/i2c-ioi2c-io communicates to an I²C device.
cmd/i2c-listi2c-list lists all I²C buses.
cmd/irir reads from an IR receiver via LIRC.
cmd/ledled reads the state of a LED or change it.
cmd/leptonlepton captures a single image, prints metadata about the camera state or triggers a calibration.
cmd/onewire-listonewire-list lists all onewire buses and devices.
cmd/periph-infoperiph-info prints out information about the loaded periph drivers.
cmd/periph-smoketestperiph-smoketest runs all known smoke tests.
cmd/periph-smoketest/gpiosmoketestPackage gpiosmoketest is leveraged by periph-smoketest to verify that basic GPIO pin functionality work.
cmd/periph-smoketest/i2csmoketestPackage i2csmoketest is leveraged by periph-smoketest to verify that an I²C EEPROM device and a DS2483 device can be accessed on an I²C bus.
cmd/periph-smoketest/onewiresmoketestPackage onewiresmoketest is leveraged by periph-smoketest to verify that a 1-wire bus search returns two devices, that a ds18b20 temperature sensor can be read, and that a ds2431 eeprom can be written and read.
cmd/periph-smoketest/spismoketestPackage spismoketest is leveraged by periph-smoketest to verify that an EEPROM device can be accessed on a SPI port.
cmd/spi-iospi-io writes to an SPI port data from stdin and outputs to stdout or writes arguments and outputs hex encoded output.
cmd/spi-listspi-list lists all SPI ports.
cmd/ssd1306ssd1306 writes to a display driven by a ssd1306 controler.
cmd/thermalthermal reads the state of thermal sensors exposed via sysfs.
cmd/tm1637tm1637 writes to a digits LED display.
connPackage conn defines core interfaces for protocols and connections.
conn/conntestPackage conntest implements fakes for package conn.
conn/displayPackage display implements interfaces for visual output devices.
conn/display/displaytestPackage displaytest contains non-hardware devices implementations for testing or emulation purpose.
conn/gpioPackage gpio defines digital pins.
conn/gpio/gpioregPackage gpioreg defines a registry for the known digital pins.
conn/gpio/gpiostreamPackage gpiostream defines digital streams.
conn/gpio/gpiostream/gpiostreamtestPackage gpiostreamtest enables testing device driver using gpiostream.PinIn or PinOut.
conn/gpio/gpiotestPackage gpiotest is meant to be used to test drivers using fake Pins.
conn/i2cPackage i2c defines the API to communicate with devices over the I²C protocol.
conn/i2c/i2cregPackage i2creg defines I²C bus registry to list buses present on the host.
conn/i2c/i2ctestPackage i2ctest is meant to be used to test drivers over a fake I²C bus.
conn/i2sPackage i2s will eventually define the API to communicate with devices over the I²S protocol.
conn/irPackage ir defines InfraRed codes for use with a IR remote control.
conn/jtagPackage jtag will eventually define the API to communicate with devices over the JTAG protocol.
conn/mmrPackage mmr defines helpers to interact with devices exposing Memory Mapped Registers protocol.
conn/onewirePackage onewire defines the API to communicate with devices over the Dallas Semiconductor / Maxim Integrated 1-wire protocol.
conn/onewire/onewireregPackage onewirereg defines a registry for onewire buses present on the host.
conn/onewire/onewiretestPackage onewiretest is meant to be used to test drivers over a fake 1-wire bus.
conn/physicPackage physic declares types for physical input, outputs and measurement units.
conn/pinPackage pin declare well known pins.
conn/pin/pinregPackage pinreg is a registry for the physical headers (made up of pins) on a host.
conn/spiPackage spi defines the API to communicate with devices over the SPI protocol.
conn/spi/spiregPackage spireg defines the SPI registry for SPI ports discovered on the host.
conn/spi/spitestPackage spitest is meant to be used to test drivers over a fake SPI port.
conn/uartPackage uart will eventually define the API to communicate with devices over the UART protocol.
devicesPackage devices is a container for device drivers.
devices/apa102Package apa102 drives a strip of APA102 LEDs connected on a SPI port.
devices/bmxx80Package bmxx80 controls a Bosch BMP180/BME280/BMP280 device over I²C, or SPI for the BMx280.
devices/bmxx80/bmx280smoketestPackage bmx280smoketest is leveraged by periph-smoketest to verify that two BME280/BMP280, one over I²C, one over SPI, read roughly the same temperature, humidity and pressure.
devices/cap1xxxPackage cap1xxx controls a Microchip cap1105/cap1106/cap1114/cap1133/cap1126/cap1128/cap1166/cap1188 device over I²C.
devices/ds18b20Package ds18b20 interfaces to Dallas Semi / Maxim DS18B20 and MAX31820 1-wire temperature sensors.
devices/ds248xPackage ds248x controls a Maxim DS2483 or DS2482-100 1-wire interface chip over I²C.
devices/leptonPackage lepton drives a FLIR Lepton Infra Red (IR) camera.
devices/lepton/cciPackage cci declares the Camera Command Interface to interact with a FLIR Lepton over I²C.
devices/lepton/image14bitPackage image14bit implements 14-bit per pixel images.
devices/lepton/internalPackage internal contains code shared between cci and lepton.
devices/lircPackage lirc implements InfraRed receiver support through native linux app lirc.
devices/ssd1306Package ssd1306 controls a 128x64 monochrome OLED display via a SSD1306 controller.
devices/ssd1306/image1bitPackage image1bit implements black and white (1 bit per pixel) 2D graphics.
devices/ssd1306/ssd1306smoketestPackage ssd1306smoketest is leveraged by periph-smoketest to verify that two SSD1306, one over I²C, one over SPI, can display the same output.
devices/tm1637Package tm1637 controls a TM1637 device over GPIO pins.
experimental/cmd/as7262as7262 communicates with an as7262 continually reading the spectrum.
experimental/cmd/hd44780hd44780 writes to a text LCD screen.
experimental/cmd/ina219ina219 communicates with an ina219 sensor reading voltage, current and power.
experimental/cmd/mcp9808mcp9808 communicates with an mcp9808 sensor reading ambient temperature.
experimental/cmd/mfrc522mfrc522 reads RFID tags.
experimental/cmd/mpu9250mpu9250 calibrates and performs the self-test, then measures the acceleration continuously.
experimental/cmd/nrzlednrzled writes to a strip of LEDs using the NRZ protocol.
experimental/cmd/pca9548pca9548 scans the 8 ports of a pca9548 i2c multiplexer for other i2c devices.
experimental/cmd/periph-webperiph-web runs a web server exposing periph's state.
experimental/cmd/tlv493dtlv493d measures the magnetic flux sensed by a tlv493d component.
experimental/conn/analogPackage analog defines analog pins, both digital to analog converter (DAC) and analog to digital converter (ADC).
experimental/conn/gpio/gpioutilPackage gpioutil includes utilities to filter or augment GPIOs.
experimental/conn/uartPackage uart defines the UART protocol.
experimental/conn/uart/uartregPackage uartreg defines the UART registry for UART ports discovered on the host.
experimental/devices/ads1x15Package ads1x15 controls ADS1015/ADS1115 Analog-Digital Converters (ADC) via I²C interface.
experimental/devices/as7262Package as7262 controls an AMS 6 channel visible spectral sensor via an i2c interface.
experimental/devices/bh1750Package bh1750 controls a ROHM BH1750 ambient light sensor, over an i2c bus.
experimental/devices/bitbangPackage bitbang implements conn by banging on the bits (GPIO pins).
experimental/devices/ccs811Package ccs811 controls CCS811 Volatile Organic Compounds sensor via I²C interface.
experimental/devices/epdPackage epd controls Waveshare e-paper series displays.
experimental/devices/epd/image2bitPackage image2bit implements two bit gray scale (white, light gray, dark gray, black) 2D graphics.
experimental/devices/hd44780Package hd44780 controls the Hitachi LCD display chipset HD-44780
experimental/devices/ht16k33Package ht16k33 implements interfacing code to Holtek HT16K33 Alphanumeric 16x8 LED driver.
experimental/devices/hx711Package hx711 implements an interface to the 24-bits HX711 analog to digital converter.
experimental/devices/ina219Package ina219 controls a Texas Instruments ina219 high side current, voltage and power monitor IC over an i2c bus.
experimental/devices/ina219/ina219smoketestPackage ina219smoketest tests the ina219 device.
experimental/devices/inkyPackage inky drives an Inky pHAT or wHAT E ink display.
experimental/devices/mcp23xxxPackage mcp23xxx provides driver for the MCP23 family of IO extenders
experimental/devices/mcp9808Package mcp9808 controls a Microchip MCP9808 digital I²C temperature sensor.
experimental/devices/mcp9808/mcp9808smoketestPackage mcp9808smoketest implements a smoke test for the mcp9808.
experimental/devices/mfrc522Package mfrc522 controls a Mifare RFID card reader.
experimental/devices/mfrc522/commandsPackage commands contains the command that a MFRC522 supports.
experimental/devices/mpu9250Package mpu9250 MPU-9250 is a 9-axis MotionTracking device that combines a 3-axis gyroscope, 3-axis accelerometer, 3-axis magnetometer and a Digital Motion Processor™ (DMP)
experimental/devices/mpu9250/accelerometerPackage accelerometer contains constants for the MPU9250.
experimental/devices/mpu9250/regPackage reg defines constants for the MPU9250.
experimental/devices/nrzledPackage nrzled is a driver for LEDs ws2811/ws2812/ws2812b and compatible devices like sk6812 and ucs1903 that uses a single wire NRZ encoded communication protocol.
experimental/devices/pca9548Package pca9548 is a driver for an 8 port I²C multiplexer that is available from multiple vendors.
experimental/devices/pca9685Package pca9685 includes utilities to controls pca9685 module and servo motors.
experimental/devices/piblasterPackage piblaster implements interfacing code is piblaster.
experimental/devices/rainbowhatPackage rainbowhat implements interfacing code to Pimoroni's Rainbow hat.
experimental/devices/sn3218Package sn3218 controls a SN3218 LED driver with 18 LEDs over an i2c bus.
experimental/devices/st7567Package st7567 implements an interface to the single-chip dot matrix LCD
experimental/devices/tlv493dPackage tlv493d implements interfacing code to the Infineon TLV493D haff effect sensor.
experimental/devices/unicornhdPackage unicornhd implements interfacing code to Pimoroni's Unicorn HD hat.
experimental/driverskeletonPackage driverskeleton is an example that can be copy pasted to help write a new driver, either in devices/ or in host/.
experimental/host/mt7688Package mt7688 interfaces with the MediaTek MT7688 MIPS CPU used on low cost board.
experimental/host/netlinkPackage netlink implements host drivers based on the Linux netlink connector interface.
experimental/host/pruPackage pru exposes the Programmable Real-Time Unit Subsystem and Industrial Communication Subsystem (PRU-ICSS) functionality found on many Texas Instruments processors.
experimental/host/serialPackage serial implements cross platform UART support exposed by the operating system.
hostPackage host defines the host itself.
host/allwinnerPackage allwinner exposes the GPIO functionality that is common to all AllWinner processors.
host/allwinner/allwinnersmoketestPackage allwinnersmoketest verifies that allwinner specific functionality work.
host/am335xPackage am335x exposes functionality for the Texas Instruments Sitara AM335x processor family.
host/bcm283xPackage bcm283x exposes the BCM283x GPIO functionality.
host/bcm283x/bcm283xsmoketestPackage bcm283xsmoketest verifies that bcm283x specific functionality work.
host/beaglePackage beagle regroups subpackages containing BeagleBoard/BeagleBone board family headers definition.
host/beagle/blackPackage black implements headers for the BeagleBone Black and BeagleBone Black Wireless micro-computers.
host/beagle/bonePackage bone implements headers J1, P8 and P9 found on many (but not all) BeagleBone micro-computer.
host/beagle/greenPackage green implements headers for the BeagleBone Green and BeagleBone Green Wireless micro-computers.
host/chipPackage chip contains header definitions for NextThing Co's C.H.I.P.
host/chip/chipsmoketestPackage chipsmoketest is leveraged by periph-smoketest to verify that basic CHIP specific functionality works.
host/cpuPackage cpu implements functions relating to the host CPU itself.
host/distroPackage distro implements common functionality to auto-detect features on the host; generally about linux distributions.
host/fsPackage fs provides access to the file system on the host.
host/odroidc1Package odroidc1 contains header definitions for Hardkernel's ODROID C0, C1, and C1+ boards.
host/odroidc1/odroidc1smoketestPackage odroidc1smoketest is leveraged by periph-smoketest to verify that basic ODROID-C1 specific functionality works.
host/pine64Package pine64 contains Pine64 hardware logic.
host/pmemPackage pmem implements handling of physical memory for user space programs.
host/rpiPackage rpi contains Raspberry Pi hardware logic.
host/sysfsPackage sysfs implements a sane library to interact with sysfs provided hardware access.
host/sysfs/sysfssmoketestPackage sysfssmoketest verifies that sysfs specific functionality work.
host/videocorePackage videocore interacts with the VideoCore GPU found on bcm283x.

Package periph imports 4 packages (graph) and is imported by 68 packages. Updated 2021-01-01. Refresh now. Tools for package owners.