Class Name
I2C
Description
Opens an I2C interface as master.
I2C is a serial bus, commonly used to attach peripheral ICs (Integrated
Circuits) to processors and microcontrollers. It uses two pins, SDA (for
data) and SDL (for the clock signal). Multiple "slave" devices can be
connected to the same bus, as long as they are responding to different
addresses (see below).
The I2C "master" device initiates a transmission, which includes sending the
address of the desired "slave" device. I2C addresses consist of 7 bits plus
one bit that indicates whether the device is being read from or written to.
Some datasheets list the address in an 8 bit form (7 address bits + R/W bit),
while others provide the address in a 7 bit form, with the address in the
lower 7 bits.
This library expects addresses in their 7 bit form, similar to Arduino's Wire
library, and what is being output by the i2cdetect utility on Linux. If the
address provided in a datasheet is greater than 127 (hex 0x7f) or there are
separate addresses for read and write operations listed, which vary exactly
by one, then you want to shift the this number by one bit to the right before
passing it as an argument to
beginTransmission().
Examples
import processing.io.*; I2C i2c; void setup() { //printArray(I2C.list()); i2c = new I2C(I2C.list()[0]); } void draw() { background(map(mouseX, 0, width, 0, 255)); // send value over I2C to an digital-to-analog // converter with address 96 (hex 0x60) int val = int(4095 * map(mouseX, 0, width, 0.0, 1.0)); i2c.beginTransmission(0x60); i2c.write(val >> 8); i2c.write(val & 255); i2c.endTransmission(); }
Constructors
I2C(dev)
Parameters
dev
(String)
interface name
Methods
beginTransmission()
Begins a transmission to an attached deviceclose()
Closes the I2C deviceendTransmission()
Ends the current transmissionslist()
Lists all available I2C interfacesread()
Read bytes from the attached devicewrite()
Add bytes to be written to the device
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