[En-Nut-Discussion] Questions re devUart1

[Harald Kipp]

Hi Francois,

At 08:45 18.02.2004 +0200, you wrote:
>Hi all,
>
>When I change from using devDebug1 to devUart1 for stdout it stops working.
>Has anyone experienced this? I'm sure it could be one of a multitude of
>problems.  I'm also using the devUart0 driver elsewhere in my program with
>no problems.

Ah, I see, you are already using UART1.



>Something that is also quite peculiar is that I notice that my .bss segment
>grows almost 700 bytes in size when doing the above mentioned change.  I
>don't know about other people, but when I have NUTDEBUG enabled the standard
>4K memory becomes very small indeed.  How do I enable external RAM for .bss
>and .data when working with Nut-Os?

NUTDEBUG output may not work with devUartx, some
outputs rely on polling output.

devUart statically pre-allocates it's buffers,
so better use devUsart.

For RAM usage: Using more than 4k for bss should be
no problem (for ICC, enable the external RAM option).
But I think there is a problem when using nearly 4k.



>Is there any advantage in using the new usart driver above the uart for
>standard 8N1 operation?

As mentioned above, it allocates its buffers from heap.
But its also slower and increases overall interrupt
latency.


>How can I set an already active stream to also output to stdout?

This is no mailing list for C newbies - go playing
with BASIC. :-)

freopen should do that:
http://www.int.gu.edu.au/courses/2010int/tute04.html

Regards,
Harald