termios with high baud rate...

[Stan]

----- Original Message ----- 
From: "Charles Steaderman" <charlies at poliac.com>
To: "Stan" <zylog at club-internet.fr>
Cc: "rtems-users" <rtems-users at rtems.com>
Sent: Friday, January 16, 2004 4:35 PM
Subject: Re: termios with high baud rate...


> I got an error posting my original reply. This one is plain text only.
>
> - Charlie
>
> Charles Steaderman wrote:
>
> >
> >
> > Stan wrote:
> >
> >>----- Original Message ----- 
> >>From: "Charles Steaderman" <charlies at poliac.com>
> >>To: "Stan" <zylog at club-internet.fr>
> >>Cc: "rtems-users" <rtems-users at rtems.com>
> >>Sent: Thursday, January 15, 2004 9:30 PM
> >>Subject: Re: termios with high baud rate...
> >>
> >>
> >>
> >>
> >>>I have a custom 5206e board working with 60096 baud with interrupt
based
> >>>termios, although the data from the sending device is not entirely
> >>>continuous. I will see if I can find a way to quickly modify my
> >>>application to test at 115200. How are you sending a continuous stream?
> >>>
> >>>
> >>
> >>I send a text file with one terminal (PC).
> >>
> >>
> >>
> >>
> >>>I am sure that hardware handshaking will be necessary. Is that OK for
> >>>your application?
> >>>
> >>>- Charlie
> >>>
> >>>
> >>
> >>My application is a simple buffer.
> >>It must to work without hardware handshaking ( at least at 57600 ).
> >>The 5206e ColdFire is fast ( 50 Mhz ),  it should be fast enough
> >>for do it.
> >>
> >>
> > The bigger problem is not the speed of the processor, but the number
> > of buffer registers in the serial port controller. I believe that the
> > ColdFire only has a 4 byte serial port buffer. If you are running one
> > task and polling the port, I could see 57600 working. If you are
> > running interrupt driven and you have other things going on, > 57600
> > without hardware handshaking will probably be a problem. The standard
> > PC UART (16550) has 14/16 byte buffers to handle higher baud rates
> > better without hardware handshaking. Do you intend to use interrupt
> > driven or polling for your termios/serial port configuration or does
> > it not matter?
> >
> > - Charlie
>

I use interrupt driven for my termios configuration.
About the number of buffer register, I think you are rigth, it's not enough
:(


Stan.