Issue connecting to arduino

Forum 2005-2010 (read only) Hardware Troubleshooting
1

I'm having a problem connecting / uploading new code to my arduino. I had it all working, and then all of the sudden I would get something like serial port not found. I checked everything out, made sure everything was still plugged in properly and such, and it seems to be. Now, I don't even get that though, I get "error opening serial port /dev/ttyUSB0". I checked to make sure that was the right one by disconnecting it and reconnecting it, and then it gets moved to USB1, so that seems right (and there's no other ttyUSB in /dev/). I've also tried rebooting, and didn't have any luck there either (both the PC and resetting the 'duino).

Here's the stack trace from the console:

Couldn't determine program size: 
processing.app.SerialException: Error opening serial port '/dev/ttyUSB0'.
      at processing.app.Serial.<init>(Serial.java:142)
      at processing.app.Serial.<init>(Serial.java:72)
      at processing.app.Uploader.flushSerialBuffer(Uploader.java:66)
      at processing.app.AvrdudeUploader.uploadViaBootloader(AvrdudeUploader.java:73)
      at processing.app.AvrdudeUploader.uploadUsingPreferences(AvrdudeUploader.java:48)
      at processing.app.Sketch.upload(Sketch.java:1632)
      at processing.app.Sketch.exportApplet(Sketch.java:1701)
      at processing.app.Editor$41.run(Editor.java:2004)
      at java.awt.event.InvocationEvent.dispatch(InvocationEvent.java:209)
      at java.awt.EventQueue.dispatchEvent(EventQueue.java:597)
      at java.awt.EventDispatchThread.pumpOneEventForFilters(EventDispatchThread.java:269)
      at java.awt.EventDispatchThread.pumpEventsForFilter(EventDispatchThread.java:184)
      at java.awt.EventDispatchThread.pumpEventsForHierarchy(EventDispatchThread.java:174)
      at java.awt.EventDispatchThread.pumpEvents(EventDispatchThread.java:169)
      at java.awt.EventDispatchThread.pumpEvents(EventDispatchThread.java:161)
      at java.awt.EventDispatchThread.run(EventDispatchThread.java:122)
Caused by: gnu.io.UnsupportedCommOperationException: Invalid Parameter
      at gnu.io.RXTXPort.setSerialPortParams(RXTXPort.java:171)
      at processing.app.Serial.<init>(Serial.java:132)
      ... 15 more

If it matters, I'm running Ubuntu 8.10 x64 w/ the newer version of gcc-avr (4.3.2), and I followed all the other ubuntu specific instructions, like making it so that the ide was using the x64 jars..

2

It sounds like the IDE might be trying to use an invalid baud rate for the serial communication with the board. In your Arduino preferences file, what's the value of serial.debug_rate? (You can find the location of the file in the preferences dialog.) Try changing it to, say, 9600.