Re: Plus/4 RS232 woes

From: André Fachat <afachat_at_gmx.de>
Date: Mon, 03 Sep 2018 10:14:53 +0200
Message-ID: <1659e7fb048.27e0.b4d1f2b66006003a6acd9b1a7b71c3b1@gmx.de>
Hi Bo,

Am 3. September 2018 09:52:20 schrieb Bo Zimmerman <bo@zimmers.net>:

> Hello all,
>
> After check both(!) books on Plus/4 programming, and the 6551 schematic,
> and doing experimenting... I have a question.  Does anyone know the
> kosher way to change the user port RTS signal so that the modem knows to
> stop transmitting data while a program catches up?  I'm initializing the
> Command Register to 5 (RTS low/enabled, DTR enabled, IRQ, no party, no
> echo).  But bad things seem to happen when I attempt to touch it again
> to change RTS to high/disabled.  Does anyone have any knowledge or
> experience with this?

In my experience the rts/cts/dtr lines are completely broken in the ACIA.

They switch off rx and/or tx at inconvenient times and in the middle of 
transactions.

So no, I don't know a good wayof using them, sorry

André

> - Bo
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Received on 2018-09-03 11:00:20

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