Problem reading serial port

linux_chris · 01-21-2009, 02:53 PM

Hi, I have a server which is listening to multiple sources (tty0, tty1 and parport0). I am using select() with a timeout and I am able to get the data from all sources. But read() is not able to catch all the data which is coming from the COM (tty0, tty1) sources. I mean, it is able to read only 16-20 bytes at a time. If I use usleep(), before the read(), I am able to get all data. Do we have any mechanism to wait till all the data arrives except sleep()/usleep()?

Thanks in advance.

-Chris

vladmihaisima · 01-21-2009, 05:10 PM

As the serial has a very slow speed, obviously the data will arrive 'slower'. You should use read() in a while, until all the data has arrived. Of course, this means you have a protocol - a way of determining when you have transferred all the data that you need. Without further information I do not know what would be best for your case.

linux_chris · 02-04-2009, 08:55 PM

Vlad-Mihai Sima,

I have resoved the issue by adding a string terminator after each command.

Thank you,
Chris