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package com.diozero.ws281xj.apa102;
/*-
* #%L
* Organisation: diozero
* Project: Device I/O Zero - WS281x Java Wrapper
* Filename: Apa102LedDriver.java
*
* This file is part of the diozero project. More information about this project
* can be found at http://www.diozero.com/
* %%
* Copyright (C) 2016 - 2020 diozero
* %%
* Permission is hereby granted, free of charge, to any person obtaining a copy
* of this software and associated documentation files (the "Software"), to deal
* in the Software without restriction, including without limitation the rights
* to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
* copies of the Software, and to permit persons to whom the Software is
* furnished to do so, subject to the following conditions:
*
* The above copyright notice and this permission notice shall be included in
* all copies or substantial portions of the Software.
*
* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
* IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
* FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
* AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
* LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
* OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
* THE SOFTWARE.
* #L%
*/
import java.util.Arrays;
import com.diozero.api.SPIConstants;
import com.diozero.api.SpiClockMode;
import com.diozero.api.SpiDevice;
import com.diozero.ws281xj.LedDriverInterface;
/**
* Reference: https://cpldcpu.com/2014/11/30/understanding-the-apa102-superled/
* Also: https://github.com/androidthings/contrib-drivers/blob/master/apa102/src/main/java/com/google/android/things/contrib/driver/apa102/Apa102.java
*/
public class Apa102LedDriver implements LedDriverInterface {
private SpiDevice device;
private int brightness;
private int[] leds;
private byte[] spiBuffer;
public Apa102LedDriver(int controller, int chipSelect, int frequency, int numLeds, int brightness) {
device = new SpiDevice(controller, chipSelect, frequency, SpiClockMode.MODE_0, SPIConstants.DEFAULT_LSB_FIRST);
this.brightness = brightness & 0x1F;
leds = new int[numLeds];
// A start frame of 32 zero bits (<0x00> <0x00> <0x00> <0x00>)
// A 32 bit LED frame for each LED in the string (<0xE0+brightness> )
// An end frame consisting of at least (n/2) bits of 1, where n is the number of LEDs in the string.
// 1-64 LEDs => 32bits
// 65-128 LEDs =>
spiBuffer = new byte[4 + 4*numLeds + ((numLeds+63)/64)*4];
}
@Override
public void close() {
allOff();
device.close();
}
@Override
public int getNumPixels() {
return leds.length;
}
@Override
public void render() {
device.write(spiBuffer);
}
@Override
public void allOff() {
Arrays.fill(leds, 0);
Arrays.fill(spiBuffer, (byte) 0);
}
@Override
public int getPixelColour(int pixel) {
return leds[pixel];
}
@Override
public void setPixelColour(int pixel, int colour) {
leds[pixel] = colour;
int spi_pixel_index = 4*(1+pixel);
// TODO Validate this order
// A 32 bit LED frame for each LED in the string (<0xE0+brightness> )
spiBuffer[spi_pixel_index] = (byte) (0xe0 | brightness);
// FIXME The calls to getComponent isn't optimal!
spiBuffer[spi_pixel_index+1] = (byte) getBlueComponent(pixel);
spiBuffer[spi_pixel_index+2] = (byte) getGreenComponent(pixel);
spiBuffer[spi_pixel_index+3] = (byte) getRedComponent(pixel);
}
}
