How to tell there is data from UART?

Altera_Forum · ‎09-16-2005

Hi

Browsing through Altera documentation suggests I should be using the HAL with a UART.

So using the HAL how do I determine if there is data available from the UART before calling getchar()? I need my system to be doing other stuff and can't have it block while waiting for the UART to receive data. I can see I have to use the fast version of the driver so that the UART operates under interrupts but I can't see an equivalent to the old kbhit() function.

Ta,

Mike

Altera_Forum · ‎09-21-2005

Just an idea, can you fiddle with the driver to be able to look at the pointers for the receive buffer? Maybe you can work out a function like kbhit then.

Stefaan

Altera_Forum · ‎09-21-2005

open device uart in non blocking mode:

static int fdterm; // FILEDESCRIPTOR RETURNED BY OPEN

..

fdterm = open("/dev/uart1", O_RDWR | O_NONBLOCK | O_NOCTTY);

..

reading is done by

..

res=read(fdterm,uart1_tempbuff,sizeof(uart1_tempbuff)-1);

if(res>0) {

... we have received some bytes

}

Altera_Forum · ‎09-21-2005

Fischer

Thanks for your reply.

I managed to work it out for myself but it is nice to have confirmation from a expert that I am doing the right thing.

Mike