[simpits-tech] Driving LED displays via a serial line

[Ken Trager]

Rob,

The MM5451 is no longer avaible from Radio Shack - The only chip like that
from Radio Shack is the MM5450 (Cat.#: 900-6842)- the trouble with that chip
is that output bit 35 (Data Enable)  is not used for a light but a latch bit. For the
data to be loaded bit 35 must be pulled low. I brougt 7 of these chips because
you can sent one data line to all chips and just pull output bit 35 low for the chip
you want to loaded the data into. If bit 35 is not pulled low the data will not load
in into that chip.

Iam glad I got all the chips I needed from Radio Shack before there were out.

Ken Trager

Robert Favre wrote:

> It's called the mm5451, and yep, it was originally designed to drive 7
> segment displays.  While it's a serial chip in that data is fed to the
> chip in a serial fashion, my code drives it via the parallel port on
> the PC.  If you're in the U.S., Radio Shack used to have it available
> online for about 4 bucks.
>
> Rob
>
> ----- Original Message -----
> From: Gene Buckle <geneb@deltasoft.com>
> Date: Friday, May 24, 2002 1:38 pm
> Subject: Re: [simpits-tech] Driving LED displays via a serial line
>
> > Alex, the chip that people are using to drive individual LEDs was
> > originaldesigned to drive 7 segment displays.  You can use this
> > for what you need.
> > I don't recall the part number though.  I'm sure Rob Favre knows..
> >
> > g.
> >
> >
> > On Fri, 24 May 2002, Wiebe, Alex wrote:
> >
> > > Anybody doing this? If so, how?
> > >
> > > I've done some preliminary searches and I can only find chips
> > that require a
> > > clock and latch line - which is getting beyond my hardware skills.
> > >
> > > What would be sweet is a chip (much like the stuff that Ferret
> > Electronics> sells) that takes a simple 2400bps serial input and
> > drives 2 x 7 segment
> > > LEDs.
> > >
> > > I'd like to drive a 4 digit and a 2 digit display for my
> > altimeter (the 4
> > > digits for the baro setting, the 2 digits for the thousands of
> > feet). The
> > > serial line 'splitter' that I'm using to drive a couple of
> > steppers (one
> > > being the altimeter) has 3 spair outputs to drive 3 more serial
> > devices.>
> >
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