interrupt question

[Quality Quorum]

On Fri, 15 Mar 2002, Stan wrote:

> Hi,
>
> I use a board with 68k 16Mhz processor and a QUART ( 68C94 : 4 x uart).
>
> The QUART provide a timer interrupt which call  rtems_clock_tick (interval : 5 mS).
> Thus, I have four interrupts Rx  and one interrupt timer.
>
> My application use Termios support ( buffer V24), .
> It's running properly at 9600 baud but not at 19200 baud.
>
>
> At 19200 baud, the RTS/CTS handshake is never switched and no datas are reading !
> But nevertheless, the hanshake running properly at 9600...
>
> How to solve this problem ?

I suspect that your CPU is too slow to handle four streams at 19200.
Try one channel at 14400, then one at 19200 etc and see whether your
problem is load dependent.

It may be a good idea to OR all the interrupts and use a single one -
you will reduce number of context switches, naturally under low load
you will poll more registers, bu in my view it is an acceptable tradeoff.


> Thanks a lot ( for previous answer also ;) )
>
> Stan.

Thanks,

Aleksey