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From: sansom@trwrb.UUCP (Richard Sansom)
Newsgroups: comp.sys.atari.st
Subject: Re: A couple of programming questions
Message-ID: <2254@trwrb.UUCP>
Date: Wed, 29-Jul-87 11:31:15 EDT
Article-I.D.: trwrb.2254
Posted: Wed Jul 29 11:31:15 1987
Date-Received: Sat, 1-Aug-87 11:21:21 EDT
References: <8707272346.AA14688@orville.arpa>
Reply-To: sansom@trwrb.UUCP (Richard Sansom)
Distribution: world
Organization: TRW EDS, Redondo Beach, CA
Lines: 55

In article <8707272346.AA14688@orville.arpa> rowley@ORVILLE.ARPA (Karl Rowley) writes:
>
>Does anyone know how to determine what the rs-232 parameters are at any
>point in time?  They are simple enough to set with Rsconf(), but I do
>not know of a way to just read the current settings.
>

The Rsconf() call returns the old rs232 parameters in a packed long word
as follows:

    31        23        15         7
    ----------------------------------------
   |   UCR    |   RSR   |   TSR   |   SCR   |
    ----------------------------------------

    bits	value
    31-24       UCR
    23-16       RSR
    15- 8       TSR
     7- 0       SCR

If you're using the Mark Williams C compiler, you'll need to redefine
Rsconf() like this:

    #undef Rsconf
    #define Rsconf(a,b,c,d,e,f) (unsigned long)xbios(15,a,b,c,d,e,f)

(this is necessary because xbios.h defines Rsconf() as a void!)

The following C blurb will fetch the old values:

    #define UCRSHIFT 24
    #define RSRSHIFT 16
    #define TSRSHIFT 8
    #define SCRSHIFT 0

    unsigned long old_rsconf;
    int old_ucr, old_rsr, old_tsr, old_scr;

    /* BAUD and FLOW may also be -1 */
    old_rsconf = Rsconf(BAUD, FLOW, -1, -1, -1, -1);

    old_ucr = (int)(old_rsconf >> UCRSHIFT) & 0xFF;
    old_rsr = (int)(old_rsconf >> RSRSHIFT) & 0xFF;
    old_tsr = (int)(old_rsconf >> TSRSHIFT) & 0xFF;
    old_scr = (int)(old_rsconf >> SCRSHIFT) & 0xFF;

Hope this helps some.

-Rich
-- 
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  /// Richard E. Sansom                   TRW Electronics & Defense Sector \\\
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