transfer() / Libraries / Processing.org

Name

transfer()

Class

SPI

Description

Transfers data over the SPI bus

With SPI, data is simultaneously being exchanged between the master device and the slave device. For every byte that is being sent out, there's also one byte being read in.

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);
}

Syntax

.transfer(out)

Parameters

out(byte[], String, int, byte)bytes to send
out(String, byte, int)string to send
out(int, byte)single byte to send, e.g. numeric literal (0 to 255, or -128 to 127)
out(byte, int)single byte to send

Return

byte[]

This work is licensed under a Creative Commons Attribution-NonCommercial-ShareAlike 4.0 International License.