[Coco] RS-232 Pak problems

[Christopher R. Hawks]

On Sun, 4 Feb 2018 13:56:49 -0600
Allen Huffman <alsplace at pobox.com> wrote:

> > On Feb 4, 2018, at 1:34 PM, Christopher R. Hawks <chawks at dls.net>
> > wrote:
> > 
> >    If OS-9 can send, then that part of the pak is fine. If some of
> > the RSDOS terminal programs do not, perhaps they initialize the pak
> > differently as they are expecting to talk to a real modem. The OS-9
> > drivers are initializing the pak to talk to a terminal.
> 
> That would explain my experiments this morning. I have done more
> reading about the 6551 in the last 24 hours than I have done since I
> got my RS-232 pak… It looks like I need to jumper both the sending
> and receiving sides, then, to make it universal.
> 
> >> It has been very curious. As much as I don’t want it to be my
> >> hardware dying, that wold explain a lot of this weirdness.
> >> 
> > 
> >    I would try shorting all (both?) of the status outputs to all the
> > status inputs. That may fool everyone involved. You could even try
> > full loopback mode (tx to rx). The pak should return all bytes sent
> > to it.
> 
> I am just not sure what that implies. I have followed what seems to
> be the most suggested way to do this (3-wire RS232 to full port) with
> no luck. I have the diagram here:
> 
> http://subethasoftware.com/2018/02/04/help-needed-with-6551-based-rs-232-pak-to-3-wire-without-dcd/
> <http://subethasoftware.com/2018/02/04/help-needed-with-6551-based-rs-232-pak-to-3-wire-without-dcd/>
> 
> Is that what you have in mind?
> 
> 		— A

    Pretty close. I would also try connecting both jumpers together in
case DTR is not active and RTS is. (Then RTS would drive DCD if DTR
wasn't.)

    Wish I could pass one of my LED mini-testers to ya. The LEDs would
show which lines are driven.


Christopher R. Hawks
HAWKSoft
-- 
"He spoke with the wisdom that can only come from experience, like
a guy who went blind because he looked at a solar eclipse without
one of those boxes with a pinhole in it and now goes around the
country speaking at high schools about the dangers of looking at
a solar eclipse without one of those boxes with a pinhole in it."
		-- Joseph Romm, Washington
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