[ECOS] Serial link problems

[Gary Thomas]

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.

-- 
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Gary Thomas                 |  Consulting for the
MLB Associates              |    Embedded world
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