Path: utzoo!utgpu!jarvis.csri.toronto.edu!mailrus!nrl-cmf!ukma!xanth!nic.MR.NET!umn-d-ub!uwvax!astroatc!nicmad!madnix!perry
From: perry@madnix.UUCP (Perry Kivolowitz)
Newsgroups: comp.sys.amiga.tech
Subject: Re: DTR and serial.device
Summary: Not A Good Idea
Keywords: serial, RS232, modem
Message-ID: <443@madnix.UUCP>
Date: 31 Jan 89 06:42:09 GMT
References: <10511@well.UUCP> <15000@oberon.USC.EDU>
Reply-To: perry@madnix.UUCP (Perry Kivolowitz)
Distribution: usa
Organization: ASDG Incorporated
Lines: 35

Marco's suggestion to access the CIA registers directly for toggling
DTR is *not* a good idea for  the  following reason: No other serial
port besides the internal one uses the CIA.

In other words, in this as in  all  things,  going  to  the hardware
directly will bind you  into some pretty severe limitations. In this
case manipulating DTR in  the suggested manner is a sure file way to
never be able to use expansion serial ports.

Another suggestion:

(Bryce are you listening? :-)

In an earlier incantation of my serial device driver I added a command
which would allow access to all setable outputs. Something like:

io_Command = CMD_SET_SERIAL_CTRL_LINES;
io_Length  = MASK_OF_BITS_TO_BE_AFFECTED;
io_Actual  = WHAT_TO_SET_THEM_TO;

DoIO(IOB)

If we all agree to make this a standard, well then, it will become a
standard.

Note: My current serial device driver (the one that deals quite nicely
with 115KB :-) does  not  have this feature anymore but I might add it
back in if there's any requests.


-- 
Perry Kivolowitz, ASDG Inc.
                          
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