|Home > Programming Reference > UARTs|
When the Foundation Platform starts, it initializes four UARTs. For each UART, it searches for a free TCP port to use for telnet access to the UART. It searches by sequentially scanning a range of 100 ports and using the first free port. The start port defaults to 5000 and you can change it using the --uart-start-port command-line parameter.
Connecting a terminal or program to the given port displays and receives output from the associated UART and permits input to the UART.
If no terminal or program is connected to the port when data is output from the UART, a terminal is started automatically.
DISPLAYenvironment variable is set and is not empty.
For the UART output to be visible, both
telnet must be installed on the host, and be specified in your PATH.
Alternatively you can redirect output from each of the four available UARTs to a file or to stdout, using the
--uart command-line parameter, where
N is in the range 0-3. Specifying a filename of
- redirects the output to stdout.