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This reference is for Processing 3.0+. If you have a previous version, use the reference included with your software in the Help menu. If you see any errors or have suggestions, please let us know. If you prefer a more technical reference, visit the Processing Core Javadoc and Libraries Javadoc.

Class | I2C
Name | ### read()
Examples |
    import processing.io.*;
    I2C compass;

    void setup() {
      //printArray(I2C.list());
      compass = new I2C(I2C.list()[0]);
    }

    void draw() {
      // read the heading over I2C from a compass module
      // with address 33 (hex 0x21)
      compass.beginTransmission(0x21);
      // first send a command byte
      compass.write(0x41);
      // read in two bytes
      byte[] in = compass.read(2);

      // put bytes together to tenth of degrees
      // & 0xff makes sure the byte is not interpreted as a negative value
      int deg = (in[0] & 0xff) << 8 | (in[1] & 0xff);
      println((deg / 10.0));
    }
Description | Read bytes from the attached device You must call beginTransmission() before calling this function. This function also ends the current transmission and sends any data that was queued using write() before. It is not necessary to call endTransmission() after read().
Syntax |
    .read(len)
Parameters |
len | int: number of bytes to read
Returns | byte[]

Updated on July 4, 2018 11:56:46am EDT