I experience the same problem, intermittently. I am using a direct serial interface on the Pi board, UART5 to be precise, mapped to ttyAMA1. This port is hardwired to the NEQ6 controller board, through level converters. Another port, UART0, is used for GPS and is mapped to ttyAMA0.

The error I get is: "Port /dev/ttyAMA1 is already used by another driver or process."

What I would like to know to help me debugging is what exactly is causing the software to output this message?

The problem may be HW related, but could equally well be an Ubuntu/Raspberry driver issue.

Thanks,
Arjan

Read More...