usbserial strange problem on Mac OS X 10.6

31 Oct 2011

Hello all,

I am trying to figure out why I am getting a strange error when I run 3 different terminal programs to monitor the mbed's usbserial connection.

If I run an mbed app that sends characters thru the usbserial, then run either ZTerm, Serial Tools, or GoSerial, I see the chars that were stored in the buffer on the mac.

At this point, all other chars that are sent from the mbed either become garbled, or simply will not display.

If I type characters on the keyboard, I see the mbed's communication led blinking, but there is no response from the app.

It's as if somehow when I run the terminal app, it messes up the communication between it and the usbserial connection.

If I try to restart the terminal app, I still get no response! I don't see any error msgs telling me that the usbserial port is offline or unavailable.

Does anybody have any suggestions or ideas about why this is happening?

Thanks!!

Chris

31 Oct 2011

Okay, I found out what is going on now.

By default, the mac's generic usbserial driver defaults to 9600,n,8,1, and the buffer is enabled as soon as OSX has booted.

I was setting the baud rate to 115k,n,8,1 in the terminal programs. That is why I could see the chars in the buffer before I ran the terminal apps, and also why additional chars sent from the mbed became garbled or invisible.

I just changed the baud rate for all the terminal apps to default to 9600,n,8,1 for now.

All is working ok now!!!

Chris