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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.

Name | ### SPI
Examples |
    import processing.io.*;
    SPI adc;

    void setup() {
      //printArray(SPI.list());
      adc = new SPI(SPI.list()[0]);
      adc.settings(500000, SPI.MSBFIRST, SPI.MODE0);
    }

    void draw() {
      // read in values over SPI from an analog-to-digital
      // converter
      // dummy write, actual values don't matter
      byte[] out = { 0, 0 };
      byte[] in = adc.transfer(out);
      // some input bit shifting according to the datasheet
      int val = ((in[0] & 0x1f) << 5) | ((in[1] & 0xf8) >> 3);
      // val is between 0 and 1023
      println(val);
    }
Description | Opens an SPI interface as master Serial Peripheral Interface (SPI) is a serial bus, commonly used to communicate with sensors and memory devices. It uses four pins: MOSI (Master Out Slave In), MISO (Master In Slave Out), and SCLK (clock signal) - those three are shared among all devices on the bus - as well as one or more SS (Slave Select) pins, that are used for the master to signal to the slave device that it is the desired respondent for the transmission. The "master" device initiates a transfer by pulling the SS pin of the "slave" low, and begins outputting a clock signal. In SPI, both the "master" as well as the "slave" device output data at the same time. It is hence not possible to read data without writing some (even if it means outputting zeros or other dummy data). There are multiple possible configuration settings for SPI, see settings() for details. This library supports multiple SPI objects making use of the same SPI interface.
Methods |
close() | Closes the SPI interface
list() | Lists all available SPI interfaces
settings() | Configures the SPI interface
transfer() | Transfers data over the SPI bus
Constructor |
    SPI(dev)
Parameters |
dev | String: device name

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