### Hardware I/O

The Hardware I/O library allows access to the computer's hardware periperals, such as digital inputs and outputs, serial busses, and the like, in a fashion similar to the Arduino plaform. This library is only available for embedded Linux boards with the necessary kernel drivers, such as the Raspberry Pi.

The source code is available on the processing GitHub repository. Please report bugs here.

##### GPIO

The GPIO class reads and writes from General Purpose I/O pins.
pinMode()
digitalWrite()
digitalRead()
attachInterrupt()
noInterrupts()
interrupts()
releaseInterrupt()
waitFor()
releasePin()

##### I2C

The I2C class communicates with peripherals over I2C interfaces.
I2C
list()
beginTransmission()
write()
read()
endTransmission()
close()

##### LED

The LED class controls the computer's build-in lights.
LED
list()
brightness()
close()

##### PWM

Use the SoftwareServo class below for the time being. Hardware PWM has yet to be made available by the hardware platforms we support.
PWM
list()
set()
clear()
close()

##### SoftwareServo

The SoftwareServo class controls RC servo motors attached to General Purpose I/O pins.
SoftwareServo
attach()
write()
attached()
detach()

##### SPI

The SPI class communicates with attached devices over SPI interfaces.
SPI
list()
settings()
transfer()
close()