pigpio is a C library for the Raspberry which allows control of the General Purpose Input Outputs (GPIO).
- Sampling and time-stamping of GPIO 0-31 between 100,000 and 1,000,000 times per second
- Provision of PWM on any number of the user GPIO simultaneously
- Provision of servo pulses on any number of the user GPIO simultaneously
- Callbacks when any of GPIO 0-31 change state (callbacks receive the time of the event accurate to a few microseconds)
- Notifications via pipe when any of GPIO 0-31 change state
- Callbacks at timed intervals
- Reading/writing all of the GPIO in a bank (0-31, 32-53) as a single operation
- Individually setting GPIO modes, reading and writing
- Socket and pipe interfaces for the bulk of the functionality in addition to the underlying C library calls
- Construction of arbitrary waveforms to give precise timing of output GPIO level changes (accurate to a few microseconds)
- Software serial links, I2C, and SPI using any user GPIO
- Rudimentary permission control through the socket and pipe interfaces so users can be prevented from "updating" inappropriate GPIO
- Creating and running scripts on the pigpio daemon
The library provides a number of control interfaces
- the C function interface,
- the /dev/pigpio pipe interface,
- the socket interface (used by the pigs utility and the Python module).
A number of utility programs are provided:
- the pigpiod daemon,
- the Python module,
- the piscope digital waveform viewer,
- the pigs command line utility,
- the pig2vcd utility which converts notifications into the value change dump (VCD) format (useful for viewing digital waveforms with GTKWave).
ALL GPIO are identified by their Broadcom number. See http://elinux.org.
There are 54 GPIO in total, arranged in two banks.
Bank 1 contains GPIO 0-31. Bank 2 contains GPIO 32-54.
A user should only manipulate GPIO in bank 1.
There are at least three types of board:
- Type 1
- 26 pin header (P1)
- Hardware revision numbers of 2 and 3
- User GPIO 0-1, 4, 7-11, 14-15, 17-18, 21-25
- Type 2
- 26 pin header (P1) and an additional 8 pin header (P5)
- Hardware revision numbers of 4, 5, 6, and 15
- User GPIO 2-4, 7-11, 14-15, 17-18, 22-25, 27-31
- Type 3
- 40 pin expansion header (J8)
- Hardware revision numbers of 16 or greater
- User GPIO 2-27 (0 and 1 are reserved)
It is safe to read all the GPIO. If you try to write a system GPIO or change its mode you can crash the Pi or corrupt the data on the SD card.