io.silverspoon.bulldog.devices.pwmdriver.PCA9685 Maven / Gradle / Ivy

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package io.silverspoon.bulldog.devices.pwmdriver;

import java.io.IOException;
import java.util.ArrayList;
import java.util.Collections;
import java.util.List;

import io.silverspoon.bulldog.core.gpio.Pin;
import io.silverspoon.bulldog.core.gpio.Pwm;
import io.silverspoon.bulldog.core.io.bus.i2c.I2cBus;
import io.silverspoon.bulldog.core.io.bus.i2c.I2cConnection;
import io.silverspoon.bulldog.core.io.bus.i2c.I2cDevice;
import io.silverspoon.bulldog.core.util.BulldogUtil;

public class PCA9685 extends I2cDevice {

   private static final String ERROR_INVALID_CHANNEL = "Invalid Channel %d - There are 16 channels on this driver: 0 to 15.";
   private static final String NAME = "PCA9685 PWM Driver";

   private static final int PCA9685_MODE1 = 0x00;
   private static final int PCA9685_PRESCALE = 0xFE;

   private static final int PWM_BASE_ADDRESS = 0x06;

   private List channels = new ArrayList();
   private double currentFrequency = 0.0;

   private boolean isSetup = false;

   private FrequencyLookupTable lookupFrequency = new FrequencyLookupTable();

   public PCA9685(I2cConnection connection) {
      super(connection);
      setName(NAME);
      setupPwmChannels();
   }

   public PCA9685(I2cBus bus, int address) {
      this(bus.createI2cConnection(address));
   }

   private void setupPwmChannels() {
      for (int i = 0; i < 16; i++) {
         Pin pin = new Pin("P" + i, i, "P", i);
         PCA9685Pwm pwm = new PCA9685Pwm(pin, this);
         pin.getFeatures().add(pwm);
         pin.activateFeature(Pwm.class);
         channels.add(pwm);
      }
   }

   public void setFrequency(double frequency) {
      if (frequency == currentFrequency) {
         return;
      }
      try {

         setupIfNecessary();

         int prescale = 0;
         if (lookupFrequency.containsKey(frequency)) {
            prescale = lookupFrequency.get(frequency);
         } else {
            prescale = (int) Math.round(25000000.0f / (4096.0f * frequency) - 1.0);
         }

         int oldmode = readByteFromRegister(PCA9685_MODE1);
         int newmode = ((oldmode & 0x7F) | 0x10);      // sleep
         writeByteToRegister(PCA9685_MODE1, newmode);      // go to sleep
         writeByteToRegister(PCA9685_PRESCALE, prescale);   // set the prescaler
         writeByteToRegister(PCA9685_MODE1, oldmode);
         BulldogUtil.sleepMs(5);
         writeByteToRegister(PCA9685_MODE1, (oldmode | 0xa1));
      } catch (Exception ex) {
         throw new RuntimeException(ex);
      }

      this.currentFrequency = frequency;
   }

   private void setupIfNecessary() throws IOException {
      if (isSetup == false) {
         writeByteToRegister(PCA9685_MODE1, 0x0F);
         isSetup = true;
      }
   }

   public void setDuty(int channel, double duty) {
      try {
         int offValue = (int) (4096 * duty);
         int register = PWM_BASE_ADDRESS + 4 * channel;
         writeByteToRegister(register, 0);
         writeByteToRegister(register + 1, 0);
         writeByteToRegister(register + 2, offValue);
         writeByteToRegister(register + 3, (offValue >> 8));
      } catch (Exception ex) {
         throw new RuntimeException(ex);
      }

   }

   public void enableChannel(int channel) {
      setDuty(channel, getChannel(channel).getDuty());
   }

   public void disableChannel(int channel) {
      setDuty(channel, 0.0f);
   }

   public Pwm getChannel(int channel) {
      if (channel < 0 || channel > 15) {
         throw new IllegalArgumentException(String.format(ERROR_INVALID_CHANNEL, channel));
      }

      for (Pwm pwm : getChannels()) {
         if (pwm.getPin().getAddress() == channel) {
            return pwm;
         }
      }

      return null;
   }

   public List getChannels() {
      return Collections.unmodifiableList(channels);
   }

}