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RE : RE : RE : Serial link problems
- From: "Guillaume Menant" <g dot menant at ayrtontechnology dot com>
- To: "'Gary Thomas'" <gary at mlbassoc dot com>
- Cc: <ecos-discuss at sources dot redhat dot com>
- Date: Fri, 12 Jan 2007 13:21:00 +0100
- Subject: [ECOS] RE : [ECOS] RE : [ECOS] RE : [ECOS] Serial link problems
Thanks but i'ts not crucial for my use. 9600 bauds is enough. It's just for
sending commands to RedBoot.
Guillaume MENANT
-----Message d'origine-----
De?: Gary Thomas [mailto:gary@mlbassoc.com]
Envoyé?: vendredi 12 janvier 2007 13:14
À?: Guillaume Menant
Cc?: ecos-discuss@sources.redhat.com
Objet?: Re: [ECOS] RE : [ECOS] RE : [ECOS] Serial link problems
Guillaume Menant wrote:
> I've resolved the problem by setting the baudrate to 9600 (a lower one)
Note: as Andrew pointed out, this problem is created by the fact that
RedBoot is a polled driver and your host may be sending characters faster
than it can handle them. You might be able to get by with a faster speed,
e.g. 19200.
You also might look at how your serial driver handles [polled] timeouts.
RedBoot has a timeout mechanism which is only applied on the first character
of the command line. If your serial driver's timeout support is poor (in
your HAL - I can't examine it), then this might also cause problems.
>
> Thanks for your support.
>
> Guillaume MENANT
>
> -----Message d'origine-----
> De : ecos-discuss-owner@ecos.sourceware.org
> [mailto:ecos-discuss-owner@ecos.sourceware.org] De la part de Guillaume
> Menant
> Envoyé : vendredi 12 janvier 2007 09:58
> À : ecos-discuss@sources.redhat.com
> Objet : [ECOS] RE : [ECOS] Serial link problems
>
> Thanks for your answer Gary.
>
> I've understand the same thing but isn't it a driver problem? I'm
currently
> working at 38400 bauds no parity, no handshake 8 databits 1 stopbit. Like
> you suggest, I will try at a lower baudrate like 9600 for example.
>
> I will give you some news when I tried this.
>
> Guillaume MENANT
>
> -----Message d'origine-----
> De : ecos-discuss-owner@ecos.sourceware.org
> [mailto:ecos-discuss-owner@ecos.sourceware.org] De la part de Gary Thomas
> Envoyé : jeudi 11 janvier 2007 12:11
> À : Guillaume Menant
> Cc : ecos-discuss@sources.redhat.com
> Objet : Re: [ECOS] Serial link problems
>
> Guillaume Menant wrote:
>> Hello,
>>
>> While using RedBoot on AT697 (LEON Sparc V8), I've encountered problems
>> using the serial link. It appears that the "_rb_gets_preloaded" function
>> miss few characters arriving on the serial link. For example, I send
> "help"
>> and RedBoot understands "hlp".
>>
>> I've tried to send this command with 2 different softwares:
>>
>> - The first one send the 4 ascii characters one after the other followed
> by
>> the carriage return -> RedBoot don't understand the command every time.
>> - The second one sends each character as soon as the user hit a key on
the
>> keyboard (it's hyperterminal, included in windows XP) -> RedBoot
> understand
>> the command every time.
>>
>> What can I do to resolve this problem? Obviously, it comes from the
serial
>> driver included in RedBoot (in io.c), but what kind of modification have
I
>> to do to prevent it?
>
> What you're seeing is a serial overflow, caused when characters
> come into RedBoot too quickly. Your first case, all four characters
> will be sent back to back, in the second, they'll only be sent as
> fast as the person typing them.
>
> Either run at a slower baud rate, or go with the one-character-at-a-time
> style of input.
>
--
------------------------------------------------------------
Gary Thomas | Consulting for the
MLB Associates | Embedded world
------------------------------------------------------------
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