Good point, John, on the display from elproducts. I was so impressed I added a
like to their site on my site.

For debugging without an emulator, I would use the led approach. But with the LC
D

display, I can write codes, such as state variable, timer/counters, to 'watch'
the code.
I think it's a tool that everyone needs.


John Haggins wrote:

> Hi Patrick,
>
> As one beginner to another let me say I started with even less experience
> than you a couple of weeks ago and boy am I surprised at what can be done.
> I had almost exactly the same challenge of hooking up 4 x 7 segment LEDs to
> a PIC and the same question: Not enough i/o's? Using the circuit in Myke's
> book on page 264 doesn't help because even if you could do it - it would
> use all the PIC 16F84 i/o lines without leaving any for push buttons.
>
> The Answer: Well, I toyed with using a 40 pin PIC which I bought but never
> started with. Instead, I dug out a device I bought and almost forgot about
> - it is a 4 digit LCD which has on board intelligence and only requires ONE
> i/o line from the PIC. You send it serial commands and it displays whatever
> you want. There are only three connections to the device, +5v, GRND and
> Data. It cost about $   and you can see it at http://www.elproducts.com
>
> Doing it this way leave me 12 i/o lines for LED's and pushbuttons on a 16F84.
>
> The great thing is that I also got PICBasicPro; a basic compiler that
> produces PIC ASM/HEX code and that thing is AMAZING! It makes programming
> the PIC a total piece of cake, especially the serial i/o for the display -
> its just one line of code like this: SEROUT
> 1,6,[$F4,tenmins,mins,tensecs,secs] which displays a time code (4 digits)
> via pin 1, in mode 6 (N9600), and the $F4 is a configuration byte for
> things like whether or not you want leading zeros, colons etc.
>
> To me, it really makes learning PIC ASM a bit redundant unless you are
> working on something really critical. The book I found most useful was
> "Easy PIC'n" and I use the EPIC plus programmer ($39) hooked up to PC
> parallel port.
>
> Hope this helps.
> John
>
> At 11:38 AM 9/18/98 -0700, you wrote:
> >Hello all,
> >
> >I am just getting started in the PIC world, and could use some
> >help.  Not only am I a beginning PICer, I am also a software
> >engineer who is very familiar with embedded controllers but
> >couldn't design a circuit to save his life.  I'm familiar with
> >components, but I don't know how to make them work together.
> >
> >Let me tell you where I'm currently at, in order to help you
> >help me better.  I have just bought a DT001 and DT101 from
> >DonTronics, and Myke Predko's book, "Programming and
> >Customizing the Pic Microcontroller".  I'm looking forward to
> >building and playing with the platform.  I've already downloaded
> >and installed MPLAB 3.4, and I'm starting to get familiar with it
> >as well.
> >
> >The project I have in mind is a device with two 2-digit readouts
> >(four 7-segment LEDs), and two sets of 2 pushbutton inputs.  The
> >readouts will initially display "20" at powerup.  The buttons are
> >used to increment or decrement the corresponding readout by 1.
> >The software for this should be a piece of cake.  The hardware,
> >although, is a different story (for me, at least).
> >
> >At first pass, it seems to me that I do not have enough I/O lines
> >available on the 16F84 to drive four 7-segment LEDs.  That fact
> >dictates some additional circuitry that is beyond my capacity to
> >design.  Now it seems I should have bought a DT111 for the
> >extra space, but oh well, I'll just use a breadboard for now.
> >
> >If anyone of you reading this could help me come up with a
> >circuit to do what I have in mind, or point out any problems with
> >my approach, I would appreciate it very much.
> >
> >Thank you all for your time.
> >
> >Patrick Murphy
> >murphy@syspac.com  (home)
> >pmurphy@az76.honeywell.com  (work)
> >
> >



--

From: Ron Russ
   EMICROS  - Embedded Micro Software
  (http://www.emicros.com)
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