BOUNCE rtl@rtlinux.org: Approval required: Non-member submissionfrom [Evgeni Dobrev <Evgeni_Dobrev@excite.com>] (fwd)

[Der Herr Hofrat <der.herr@hofr.at>]

>From owner-rtl Tue Jun  5 01:53:34 2001
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Date: Tue, 5 Jun 2001 00:47:50 -0700 (PDT)
From: Evgeni Dobrev <Evgeni_Dobrev@excite.com>
To: rtl@fsmlabs.com
Subject: Re: [rtl] rt_com
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Hello Anders,

thank you for the advice.  Now the char is sent back between 0.055mS and
0,089 mS after the serial port receives the char (@19200).  The response
time fluctuates though between those two values in "regular" (periodic) way.
What could be the cause for this fluctuation?

Anyway now I am within the 3bits limit :). thank you very much once again.

evgeni

>  The problem is not the driver but the way the register in the serial port
is
>  set up.
>  The UART does not generate a interrupt for every char it recived if it
has't
>  been
>  tould to do so. It is the register for the input fifo.
>  I think this is what happens. ->
>  the computer recives a char.
>  It does NOT make a interrups at once but wait's.
>  It ganerate a interrupt when "No Charecters have Been removed From or
input to
>  the RCVR FIFO During the last 4 Char."
>  (thats 1/(19200/10bits) ~2mSec.)
>  The driver catch the interrupt. do what ever you wont it to and send a
byte
>  (0.2~ mSec).
>  
>  I can't remeber if it is posible to set the number of chars before
interrups
>  with the rt_setup call. If not you have to make some minor changes in the
>  driver.
>  
>  Anders Gnistrup
>  
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