Path: utzoo!mnetor!uunet!lll-winken!lll-lcc!pyramid!voder!wlbr!pete
From: pete@wlbr.EATON.COM (Pete Lyall)
Newsgroups: comp.sys.m6809
Subject: Re: rs232 Needed
Message-ID: <1156@wlbr.EATON.COM>
Date: 11 Dec 87 18:22:25 GMT
References: <15741@watmath.waterloo.edu> <3986@pucc.Princeton.EDU> <1153@wlbr.EATON.COM> <1455@cartan.Berkeley.EDU>
Reply-To: pete@wlbr.UUCP (0000-Pete Lyall)
Distribution: na
Organization: Eaton IMS, Westlake Village, CA
Lines: 42
In article <1455@cartan.Berkeley.EDU> koonce@bosco.edu (tim koonce) writes:
>In article <1153@wlbr.EATON.COM> pete@wlbr.UUCP (0000-Pete Lyall) writes:
>>In article <3986@pucc.Princeton.EDU> EWTILENI@pucc.Princeton.EDU writes:
>>>The CoCo 3 can EASILY run 1200 baud out of the bitbanger port on the back
>>>of the computer
>>
>>Wrong. Unless you wish to program the interval timer and poll the bit...
>>--
>>Pete Lyall (OS9 Users Group V.P.)
>
>Here we have an excellent example of OS9 snobbery.
>
>You're right, but only under OS9. Under RSDOS, things work
>differently. In fact, programming the interval timer and polling the
>bitbanger is pretty easy, and doesn't use up such enormous amounts of
>time as you might think, even at 2400 baud, if the routines are
>carefully written. I've done it, and it works.
Guilty as charged...
I certainly consider the OS9 environment to be an order of magnitude
more powerful than RS-DOS. And regarding RS-DOS and serial drivers,
I'm *painfully* aware of the intricacies and the pitfalls.. back in
the 'dark days' before OS9 was widely commercially available, I spent
over a year developing the machine language driver and underlayer for
the COLORAMA BBS system (the BASIC was written by Peter Banz of
Ceratec in Austin, TX - all BASIC flames to him ;^}). As an aside, it
was primarily developed under FLEX (on a COCO w/ a VT-100).
Back to present time..
I believe the interrupt logic to signal the arrival of a start bit is
still hosed up - detects and triggers on the rising edge of the bit
window.. should detect on falling. If that were the case, then I'd
agree - you wouldn't have to babysit the port waiting for start bit
arrival. Obvious solution is to short the CD line to the Rxd line and
use the carrier detect interrupt instead.
--
Pete Lyall (OS9 Users Group V.P.) Eaton Corporation (818)-706-5693
Compuserve: 76703,4230 (OS9 Sysop) OS9 (home): (805)-985-0632 (24hr./1200 baud)
Internet: pete@wlbr.eaton.com UUCP: {ihnp4,scgvax,jplgodo,voder}!wlbr!pete