pwm fails with file not found error On BeagleBoneBlack

[rickblair]

I am trying to run the PWM example. I run as root. System is BeagleBoard.org Debian Image 2015-11-12 Bulldog version is latest.

Here is the error: [java] -- listing properties -- [java] First [java] Exception in thread "main" java.lang.RuntimeException: java.io.IOException: No such file or directory [java] at io.silverspoon.bulldog.linux.sysfs.SysFs.echoAndWait(Unknown Source) [java] at io.silverspoon.bulldog.beagleboneblack.sysfs.BBBSysFs.createSlotIfNotExists(Unknown Source) [java] at io.silverspoon.bulldog.beagleboneblack.pwm.BBBPwm.setupImpl(Unknown Source) [java] at io.silverspoon.bulldog.core.pin.AbstractPinFeature.setup(Unknown Source) [java] beagleboneblack.dogtag=BeagleBoard.org Debian Image 2015-11-12 [java] [java] at io.silverspoon.bulldog.core.pin.Pin.activateFeature(Unknown Source) [java] at io.silverspoon.bulldog.core.pin.Pin.as(Unknown Source) [java] at com.honeywell.spsd.deliveryTruck.PWMTest.main(PWMTest.java:20) [java] Caused by: java.io.IOException: No such file or directory [java] at java.io.FileOutputStream.writeBytes(Native Method) [java] at java.io.FileOutputStream.write(FileOutputStream.java:326) [java] at sun.nio.cs.StreamEncoder.writeBytes(StreamEncoder.java:221) [java] at sun.nio.cs.StreamEncoder.implClose(StreamEncoder.java:316) [java] at sun.nio.cs.StreamEncoder.close(StreamEncoder.java:149) [java] at java.io.OutputStreamWriter.close(OutputStreamWriter.java:233) [java] at java.io.BufferedWriter.close(BufferedWriter.java:266) [java] ... 7 more [java] Java Result: 1

Here is the code I am trying to run:

import io.silverspoon.bulldog.core.gpio.DigitalOutput; import io.silverspoon.bulldog.core.platform.Board; import io.silverspoon.bulldog.core.platform.Platform; import io.silverspoon.bulldog.core.pwm.Pwm; import io.silverspoon.bulldog.core.pwm.SoftPwm; import io.silverspoon.bulldog.core.util.BulldogUtil; import io.silverspoon.bulldog.beagleboneblack.pwm.; import io.silverspoon.bulldog.beagleboneblack.;

public class PWMTest {

public static void main(String[] args) { final Board board = Platform.createBoard();

  //These will always share the same frequency - same pwm group! 
  Pwm pwm1 = board.getPin(BBBNames.EHRPWM0A_P9_21).as(Pwm.class); 
  Pwm pwm2 = board.getPin(BBBNames.EHRPWM0B_P9_22).as(Pwm.class); 
  pwm1.setFrequency(50.0f);  // 50 Hz 
  pwm1.setDuty(0.5f);    // 50% duty cycle 
  pwm1.enable(); 

  pwm2.setFrequency(50.0f);  // 50 Hz 
  pwm2.setDuty(0.3f);    // 30% duty cycle*/ 
  pwm2.enable(); 

  //These will always share the same frequency - same pwm group! 
  Pwm pwm3 = board.getPin(BBBNames.EHRPWM1A_P9_14).as(Pwm.class); 
  Pwm pwm4 = board.getPin(BBBNames.EHRPWM1B_P9_16).as(Pwm.class); 
  pwm3.setFrequency(1000.0f);  // 1000 Hz 
  pwm3.setDuty(0.5f);    // 50% duty cycle 
  pwm3.enable(); 

  pwm4.setFrequency(1000.0f);  // 1000 Hz 
  pwm4.setDuty(0.9f);    // 90% duty cycle 
  pwm4.enable(); 

  //These will always share the same frequency - same pwm group! 
  Pwm pwm5 = board.getPin(BBBNames.EHRPWM2A_P8_19).as(Pwm.class); 
  Pwm pwm6 = board.getPin(BBBNames.EHRPWM2B_P8_13).as(Pwm.class); 
  pwm5.setFrequency(10000.0f); // 10 kHz 
  pwm5.setDuty(0.25f);   // 25% duty cycle 
  pwm5.enable(); 

  pwm6.setFrequency(10000.0f); 
  pwm6.setDuty(0.75f);   // 75& duty cycle 
  pwm6.enable(); 

  //On some pins there are conflicts with hdmi 
  if(!board.hasProperty(BBBProperties.HDMI_ENABLED)) { 
   Pwm pwm7 = board.getPin(BBBNames.ECAPPWM0_P9_42).as(Pwm.class); 
   pwm7.setFrequency(100.0f); 
   pwm7.setDuty(0.5f); 
   pwm7.enable(); 

   Pwm pwm8 = board.getPin(BBBNames.ECAPPWM2_P9_28).as(Pwm.class); 
   pwm8.setFrequency(100.0f); 
   pwm8.setDuty(0.9f); 
   pwm8.enable(); 
  } 

  // This is a software pwm. It has kind of high cpu costs  
  // and is far from precise, but it can be used to drive  
  // motors for example and can be set up on any digital output 
  Pwm softPwm = new SoftPwm(board.getPin(BBBNames.P8_12)); 
  softPwm.setFrequency(50.0f); 
  softPwm.setDuty(0.2f); 
  softPwm.enable(); 

  for(int i = 0; i < 10; i++) { 
   for(double d = 0.0; d < 1.0; d += 0.01) { 
    pwm5.setDuty(d); 
    pwm6.setDuty(d); 

    BulldogUtil.sleepMs(1); 
   } 

   for(double d = 1.0; d > 0.0; d -= 0.01) { 
    pwm5.setDuty(d); 
    pwm6.setDuty(d); 

    BulldogUtil.sleepMs(1); 
   } 
  } 

  System.out.println("You can exit with ctrl + c"); 
  while(true) { 
   BulldogUtil.sleepMs(100); 
  } 

}

[Aidan275]

@rickblair I'm getting the same errors, did you ever solve this issue?

[rickblair]

Wow that was a while back. I believe I rolled back to an earlier version of Debian. The way the hardware mapping for GPIO changed between kernel versions.

Sorry I don't have the version info anymore.