Problem using UART port with serial device

Altera_Forum · ‎05-28-2015

Hi,

My configuration:

-Altera cycloneV socDevKit

-Linux kernel : 3.9.0 and debian filesystem from this rocketboards project : http://www.rocketboards.org/foswiki/projects/debian

I'm trying to communicate with a serial GPS module (4800 8N1) plugged on the UART mini USB port. But I can't read data from the device.

It works fine when I use a PC with a terminal. I even disabled the login prompt in /etc/inittab to directly read data send from the device but nothing happend.

Anyone have solution ?

Maybe a driver problem or tty settings ?

Use HPS USB port could be better ?

Thanks.

Altera_Forum · ‎08-29-2015

Hi,

since you're using Linux, is it possible that cooked mode makes problems? If you just open a /dev/ttyWhatver port, it is configured in cooked mode by default. That would explain why you cannot read: your OS buffers all input and holds it back until a termination character arrives, but probably your device does not send such a character. The "PC with a terminal" you mentioned probably uses raw mode by default.

Info about raw/cooked modes: http://stackoverflow.com/questions/13104460/c-confusion-about-raw-vs-cooked-terminal-modes (http://stackoverflow.com/questions/13104460/c-confusion-about-raw-vs-cooked-terminal-modes)

What helped me to solve that in C/C++ (I assume you want to solve the problem in a C/C++ program since you posted it here): http://stackoverflow.com/questions/6947413/how-to-open-read-and-write-from-serial-port-in-c (http://stackoverflow.com/questions/6947413/how-to-open-read-and-write-from-serial-port-in-c)

Best regards,

GooGooCluster