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From: daniel@sickkids.UUCP (Daniel Guerin )
Newsgroups: comp.sys.mac
Subject: Serial drivers question and ROM differences
Message-ID: <56@sickkids.UUCP>
Date: Tue, 2-Jun-87 09:10:57 EDT
Article-I.D.: sickkids.56
Posted: Tue Jun  2 09:10:57 1987
Date-Received: Wed, 3-Jun-87 05:26:01 EDT
Organization: Hospital for Sick Children, Toronto
Lines: 22

I am puzzled by a couple of things with the serial drivers; may be a more
experienced soul could shed some light.

1) IM (the original edition) says that the ROM serial driver does not support
handshake;  however, on both a 512E and an SE the ROM driver *does* Xon/Xoff
handshaking (I can see it on my breakout box) on at least the modem port (I
have not tried with the printer port).  Of course I do enable Xon/Xoff
with a SerHShake call.  I looked through the documentation, and although TN #57
says that SERD 0 is in the 128K ROMs, it does not say that the ROM and the
RAM serial drivers are the same.  Is RAMSDOpen just a no-op with the 128K and
SE ROMs?  Should it still be called for compatibility with the 64K ROMs?

2) When I close a serial driver with CloseDriver, DTR (Handshake out, pin 1 on
the mini-8 connector) drops on an SE, but *remains asserted* on a 512E.  Is
this behaviour normal?  Is there a way to keep DTR asserted on the SE other
than by not closing the driver?  I also tried to call RAMSDOpen/RAMSDClose,
and the behaviour is the same: RAMSDClose causes DTR to drop on the SE only.

Thanks in advance for the help.

Daniel Guerin, The Hospital for Sick Children
UUCP: {decvax,utzoo}!sickkids!daniel	BITNET: daniel@sickkids.utoronto