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RE: Serial getc problem


On Mon, 2002-07-08 at 10:35, George Sosnowski wrote:
> I have come across a similar situation using the 860T. My platform has
> one serial port (SMC1 used as diag and console port) and currently I
> inherit the serial channel from redboot. Is it still possible to have a
> 'proper' /dev/tty0 that uses the inherited serial channel (diag/console)
> from redboot? Or does the ecos ram image have to install its own
> /dev/ser0 for console and diag channels since these are the same device?
> 

If you want non-blocking (i.e. interrupt driven) I/O, you need to use 
/dev/ser0.  I/O through the default console /dev/ttydiag will always be
blocking (non interrupt driven).  For the most part, these can usually
co-exist, with the caveats that output from the non-interrupting device
could intermingle with that from the interrupting device and that if you
use GDB features then only blocking I/O will be used while GDB is in
control.

> Thanks,
> George
> 
> -----Original Message-----
> From: Robert Cragie [mailto:rcc@jennic.com] 
> Sent: Thursday, July 04, 2002 10:26 AM
> To: Daniel Lidsten; ecos-discuss@sources.redhat.com
> Subject: RE: [ECOS] Serial getc problem
> 
> You need to use a 'proper' serial driver (/dev/tty0 or /dev/tty1), not
> /dev/ttydiag. These allow blocking reads which will allow other threads
> to
> run; as you  have seen, /dev/ttydiag does a busy wait on a character
> which
> will stop other threads from running. You can configure eCos so that
> stdio
> uses /dev/tty0 or /dev/tty1.
> 
> Regards,
> 
> Robert Cragie, Design Engineer
> 
> Direct: +44 (0) 114 281 4512
> ________________________________________________________
> Jennic Ltd, Furnival Street, Sheffield, S1 4QT,  UK
> www.jennic.com  Tel: +44 (0) 114 281 2655
> 
> 
> > -----Original Message-----
> > From: ecos-discuss-owner@sources.redhat.com
> > [mailto:ecos-discuss-owner@sources.redhat.com]On Behalf Of Daniel
> > Lidsten
> > Sent: 04 July 2002 17:19
> > To: ecos-discuss@sources.redhat.com
> > Subject: [ECOS] Serial getc problem
> >
> >
> > Hi,
> >
> > I am running a MPC850 with a few different threads in the application.
> > The network stack is also enabled and up and running. However, when a
> > thread calls the HAL_DIAG_READ_CHAR to wait for input from the user
> then
> > my net stack stops working. I cant reach it with a ping from my local
> > host.
> >
> > My first thought was that the application was running with a higher
> > priority (lower value) then the net stack but that was not the case.
> The
> > application runs at prio 8 and net at 6 and 7 (background).
> >
> > I have seen in the serial driver that when reading a char from the
> port
> > then the following is done:
> >
> > while ( !getc_non_block(..) )
> >
> > Can the problem be that this code is running in some form of "kernel
> > state" i.e. in a very high prio state since the driver lies within
> eCos?
> >
> > Regards, Daniel
> >
> > --
> > Before posting, please read the FAQ:
> http://sources.redhat.com/fom/ecos
> > and search the list archive: http://sources.redhat.com/ml/ecos-discuss
> >
> >
> 
> 
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> 
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