Class Name
SPI
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.
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); }
Constructors
SPI(dev)
Parameters
dev
(String)
device name
Methods
close()
Closes the SPI interfacelist()
Lists all available SPI interfacessettings()
Configures the SPI interfacetransfer()
Transfers data over the SPI bus
This work is licensed under a Creative Commons Attribution-NonCommercial-ShareAlike 4.0 International License.