Article View: net.micro.amiga
Article #4981Re: Mechanics of dropping DTR
From: Marnix van Ammers
Date: Fri, 17 Oct 1986 04:43
Date: Fri, 17 Oct 1986 04:43
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2828 bytes
In article <257@hao.UUCP> hull@hao.UUCP (Howard Hull) writes:
>In article <305@pttesac.UUCP>, vanam@pttesac.UUCP (Marnix van Ammers) writes:
>> ... according to Wecker, the [VT100] program does
>> *not* leave DTR on. So now I've found that this thing that I thought
>> was a feature, actually only happens under certain circumstances. I'm
>> trying to isolate just when I get this feature. For some reason I
>> could not get the feature to work at all last night (DTR kept going off
>> when I quit the program) but I swear, the night before it was working
>> just as I've said: DTR remained on...
>
>Ah ha... I had the same sensation of inconsistency about Wecker's VT100 and
>the behavior of DTR dependent interfaces. I finally discovered that what I
>had done was to invoke another terminal program which doesn't reset DTR,
>quit that, and then fire up VT100. I read somewhere that the serial device
>keeps a cumulative count of the number of devices that have requested use
>of the port. Those that open the device properly increment the count, and
>those that close the device properly decrement the count. If you have a
>program that fails to close properly when it quits, then the device count
>is already at least one when VT100 starts up. Thus when VT100 quits, the
>count remains greater than zero and DTR remains asserted.
Howard is right. Just last night I discovered that when I use
maxicomm first and then vt100, when I quit the vt100 program then
DTR remains ON. Now I *think* (still need to check this out) that
no matter how many times I run maxicomm, DTR is always turned off
when I quit the program. Something doesn't quite make sense there.
But no matter how many times I run vt100 after once having run
maxicomm, DTR stays on when I quit.
Since I like DTR to remain on most of the time (but not always!)
I guess I can run maxicomm first. Seems like it must be possible to
come up with a tiny little program that will do this for me. That
makes it also possible to have a configurable (via vt100.init) DTR
ON option. At least so I think.
Marnix
--
Marnix A. van\ Ammers
Home: (707) 644-9781 Work: (415) 545-8334
{ihnp4|ptsfa}!pttesac!vanam CIS: 70027,70
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Relay-Version: version B 2.10 5/3/83; site utzoo.UUCP Path: arc1-ca.pugleaf.net!utzoo!mnetor!seismo!lll-crg!lll-lcc!unisoft!dual!ptsfa!pttesac!vanam From: vanam@pttesac.UUCP (Marnix van Ammers) Newsgroups: net.micro.amiga Subject: Re: Mechanics of dropping DTR Message-ID: <308@pttesac.UUCP> Date: Fri, 17-Oct-86 00:43:15 EDT Article-I.D.: pttesac.308 Posted: Fri Oct 17 00:43:15 1986 Date-Received: Fri, 17-Oct-86 06:06:05 EDT References: <305@pttesac.UUCP> <257@hao.UUCP> Reply-To: vanam@pttesac.UUCP (Marnix van Ammers) Organization: Pacific Bell ESAC, San Francisco Lines: 40