Groups > comp.os.linux.development.apps > #158

Re: termios

Date	2011-06-18 20:01 +0200
From	michel simian <michel@simian.fr>
Newsgroups	comp.os.linux.development.apps
Subject	Re: termios
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Tauno Voipio écrivit de sa plume:
> You have found the hard core of RS-485 communications.
> 
> The problem is to control the transmiter enable so that
> your last character is wholly transmitted, but the response
> is not arriving yet, when the transmitter (RTS) is turned off.
> 
> Most serial interface chips report ready well ahead in time
> before the last character has even started to send. If the
> chip can report 'transmitter idle', you can use it, else
> you need to have a well-adjusted delay after sending.
> 

OK. Thank you.

So, the first hypothesis is that the chip do that,
and the linux driver is correct. Then, when I return
from write operation, (or from a select on the dedicated
write fd_set file descriptor), I can read :

- the bytes from the echo
- and the device answer

But it does not work as described.

If I try to read the echoed bytes before, the analyzer does
not show the bytes sent... and I think they are not sent.

Then, 2nd hypothesis: the chip and the linux driver
does not do the right job, and I must adjust some
'usleep' when I hope they are efficient ?

Yep, may I hope succeeding without putting candles ?

-- 
L'Amer Michel

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Thread

termios michel simian <michel@simian.fr> - 2011-06-17 17:14 +0200
  Re: termios Jan Panteltje <pNaonStpealmtje@yahoo.com> - 2011-06-17 17:01 +0000
  Re: termios Grant Edwards <invalid@invalid.invalid> - 2011-06-17 20:19 +0000
    Re: termios michel simian <michel@simian.fr> - 2011-06-18 17:17 +0200
      Re: termios Tauno Voipio <tauno.voipio@notused.fi.invalid> - 2011-06-18 19:38 +0300
        Re: termios michel simian <michel@simian.fr> - 2011-06-18 20:01 +0200
          Re: termios Tauno Voipio <tauno.voipio@notused.fi.invalid> - 2011-06-18 22:44 +0300
            Re: termios michel simian <michel@simian.fr> - 2011-06-19 06:56 +0200
            Re: termios michel simian <michel@simian.fr> - 2011-06-24 19:28 +0200
              Re: termios Tauno Voipio <tauno.voipio@notused.fi.invalid> - 2011-06-24 21:42 +0300
                Re: termios Grant Edwards <invalid@invalid.invalid> - 2011-06-26 02:27 +0000

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