Ed Anderson wrote:

 > > I am attempting to use as much as I can of the chip.  I am able to
store

default values in the EEPROM area - such as fuel remaining, Fuel

Reserve,

etc.  I've decided to also used the A/D feature to drive the

air/fuel

indicator - may not have it up and running on the first go around,

but

will

have the board wired for it.   Does not look like interface to a

seperate

EEPROM chip would be difficult - but, then I have not gotten that

far

yet in

my research.

Probably bitting off more than I should - as all the guidance says

start

with a simple program, but at least as I work out the bugs I feel

like

I'm

making progress in both the learning and the program.  Now if I can

just

get

the 255 bits from an 8 bit A/D to correlate to LED lights driven by

the

7

Seg driver which also drives the 7 seg numeric displays and remember

to

multiplex 7 digits (3 digits for flow rate and fuel usage each = 6

plus

the

1 for driving the LED) I'll be on my way. {:>).

Lucky I have a high tolerance for frustration {:>)

Ed

You are not using a simple 7 segment LED are you Ed?
I have not done one of those for the last thirty years :-)
Shessss! this is the 21st century. What you need is a smart
display. You send it ASCII and it does the rest.
HP makes a super bright version that all the high buck avionics people
use. HDSP 2112 or HDSP 2XXX. Newark Electronics. Also second
sourced by Agilent Technologies.
http://www.semiconductor.agilent.com

There is plenty of help on here ask for it.

Paul Lamar

Well, actually, Yes I was using the simple 7 segment LED mainly because

it

was "simple" {:>).  However, I was using chips that tranformed the BCD

into

the 7 Seg pattern rather than doing that in the Microchip - but, a LED

that

has that already built in would eliminate the need for that chip.

Thanks for the suggestion, I'll take a look at the HD series.

Ed Anderson

Check out some of the certified avionics at the airport to see what they
look like in actual operation. You will know one when you see it.
They are outstanding when it comes to readability. I have a few
at the hangar I was going to use for a project awhile back.
Unfortunately they are not in a circuit so I can't take a picture
of them lit up.

The other big advantage is they are dot matrix so you have
the complete ASCII set to work with and not just what you can
get with seven segments. The down side is they are a bit more
expensive but I would pay more for the end product because
it looks so professional.

Does the PIC have BCD arithmetic and other BCD functions?
The old 6502 had that and it was a godsend.  If not,
how do you plan to do the binary to ASCII conversions?

Paul Lamar

Yes, they are expensive (see previous post) , but I'll take a look at them
as they do offload the display refresh burden from the microchip.  The PIC
does not have BCD arithmetic exactly but does have some "adjusment"
functions that make BDC operations somewhat easier.  No problem on the
binary to ASCII, already have the code for that - was just a tedious pain to
program.  Depending on what display chips I use they can range from
accepting binary, BCD or ASCII as inputs.

Ed Anderson

 
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