Android I2C crash

Comments

• Eric

  July 2015

  Can you consistently cause this crash?  The line in question is code that extracts the I2C data from the MetaWear response packet and the crash is caused the response being less than 3 bytes long.
• lethala

  July 2015

  My code is under heavy development. It was happening consistently before a change I made last night but has yet to occur since. I use a timer and an event to send gyro samples over I2C whenever a gpio is low. My previous code started the timer when the pin went low and stopped it when it returned high. I changed the code to post a read of the pin whenever I received a sample and stop the timer when it went high. The reason I made the change was I dropping low to high transitions for some reason causing the sample stream to remain on. I don't know if the problem went away but It hasn't happened since that change. I'll let you know if I see it again.
• lethala

  July 2015

  It just happened again. 

  
  

  
  
• lethala

  July 2015

  I made the following change in a local copy of the library to get me past the problem.

  if (data.length > 3) {
      byte[] i2cData = new byte[data.length - 3];
      System.arraycopy(data, 3, i2cData, 0, data.length - 3);
  
      for (ModuleCallbacks it : callbacks) {
          ((Callbacks) it).receivedI2CData(data[2], i2cData);
      }
  }
  
• lethala

  July 2015

  I just got a different error.

  
  

  07-12 22:03:43.863    5043-5043/com.mbientlab.metawear.app E/AndroidRuntime﹕ FATAL EXCEPTION: main

      Process: com.mbientlab.metawear.app, PID: 5043

      java.lang.RuntimeException: Error receiving broadcast Intent { act=com.mbientlab.com.metawear.api.MetaWearBleService.Action.NOTIFICATION_RECEIVED flg=0x10 (has extras) } in com.mbientlab.metawear.api.MetaWearBleService$2@41c00190

              at android.app.LoadedApk$ReceiverDispatcher$Args.run(LoadedApk.java:788)

              at android.os.Handler.handleCallback(Handler.java:733)

              at android.os.Handler.dispatchMessage(Handler.java:95)

              at android.os.Looper.loop(Looper.java:137)

              at android.app.ActivityThread.main(ActivityThread.java:5082)

              at java.lang.reflect.Method.invokeNative(Native Method)

              at java.lang.reflect.Method.invoke(Method.java:515)

              at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:782)

              at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:598)

              at dalvik.system.NativeStart.main(Native Method)

       Caused by: java.lang.NullPointerException

              at com.mbientlab.metawear.api.MetaWearBleService.execGattAction(MetaWearBleService.java:397)

              at com.mbientlab.metawear.api.MetaWearBleService.queueCommand(MetaWearBleService.java:2401)

              at com.mbientlab.metawear.api.MetaWearBleService.queueRegisterAction(MetaWearBleService.java:2368)

              at com.mbientlab.metawear.api.MetaWearBleService.queueRegisterAction(MetaWearBleService.java:2332)

              at com.mbientlab.metawear.api.MetaWearBleService.access$1600(MetaWearBleService.java:80)

              at com.mbientlab.metawear.api.MetaWearBleService$MetaWearControllerImpl$11.readDigitalInput(MetaWearBleService.java:1636)

              at com.lethala.blink.MainActivity$1$1.receivedI2CData(MainActivity.java:195)

              at com.mbientlab.metawear.api.controller.I2C$Register$1.notifyCallbacks(I2C.java:62)

              at com.mbientlab.metawear.api.MetaWearBleService$2.onReceive(MetaWearBleService.java:343)

              at android.app.LoadedApk$ReceiverDispatcher$Args.run(LoadedApk.java:778)

              at android.os.Handler.handleCallback(Handler.java:733)

              at android.os.Handler.dispatchMessage(Handler.java:95)

              at android.os.Looper.loop(Looper.java:137)

              at android.app.ActivityThread.main(ActivityThread.java:5082)

              at java.lang.reflect.Method.invokeNative(Native Method)

              at java.lang.reflect.Method.invoke(Method.java:515)

              at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:782)

              at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:598)

              at dalvik.system.NativeStart.main(Native Method)
• Eric

  July 2015

  Are you by chance periodically scheduling readRssi (or readBatteryLevel) function calls?
• lethala

  July 2015

  "Are you by chance periodically scheduling readRssi (or readBatteryLevel) function calls?"

  
  

  No. I currently call those once each in the connected() callback method.
• Eric

  July 2015 edited July 2015

  Since you are have the source in hand, you can try replacing the single line while loop causing the error (https://github.com/mbientlab/Metawear-AndroidAPI/blob/1.8.0/app/src/main/java/com/mbientlab/metawear/api/MetaWearBleService.java#L397)

  
  

  with this expanded version:

  
  

  while(!actions.isEmpty()) {
  

      Action next= actions.poll();

      if (next != null) {

          lastResult= next.execute();

      }

  }
• lethala

  July 2015

  Thanks. I'll give that a try.