Date: Wed, 27 May 1998 13:29:32 -0700 From: Mike Smith <mike@smith.net.au> To: Peter Dufault <dufault@hda.com> Cc: marc@hippocampus.net (Marc Nicholas), small@FreeBSD.ORG Subject: Re: LCDs... Message-ID: <199805272029.NAA01723@dingo.cdrom.com> In-Reply-To: Your message of "Wed, 27 May 1998 15:00:50 EDT." <199805271900.PAA18304@hda.hda.com>
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> > > You could also drive the parallel connection on Optrex style > > > controllers through the parallel port. > > > > I would imagine this would become timing sensitive, no? > > Check Mike's code which I didn't know about. I assume there > is a minimum setup time before you twiddle a handshake - I've > done this way back and don't remember there being any problems. Yes, there are assorted weird timing constraints. The Hitachi part dominates the 1-4 line alphanumeric LCD market, and datasheets for it are available in many places across the web. As a general rule, the constraints are command-based rather than handshake-based; you would need to be talking to the LCD memory-mapped off a fairly fast micro before you ran into problems. I doubt that you can coax a parallel port into going nearly fast enough to give it any trouble. > > I'd be interested in references for I2C buttons...or keypads. If you're doing this on a product basis, you're almost certainly better off DIY with a PIC or Z8 micro and a serial interface. Buying someone else's I2C keyboard/display combo is fine for one-offs, but the pricing I've seen would indicate that you'd be wasting far too much money on it. -- \\ Sometimes you're ahead, \\ Mike Smith \\ sometimes you're behind. \\ mike@smith.net.au \\ The race is long, and in the \\ msmith@freebsd.org \\ end it's only with yourself. \\ msmith@cdrom.com To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-small" in the body of the message
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