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
Paul/Ed,
Maybe I missed it on the thread. What PIC chip are you using?
Thanks
Dean
Dean, right now I am looking at the Microchip 18F252 with three ports,
10
bit A/D channels, PW generation, PW Capture, "Flash" memory, etc.
They have a new assembler out (still in beta stage and with a few
bugs)
which is quite nice and Free!
Ed Anderson
Ed,
I was looking into the possibilities of using some single chip micros
for
instrumentation also. I have been away from the hardware/software for a
while and I am really excited to see what's available for these purposes
now. I had also kicked around the idea of trying to use something like
an
iPAQ as the base platform but, started bumping the wall when I tried to
find
info on interfacing to it. Have you seen any info on such interfaces?
Thanks
Dean
Dean, the link below is the only thing I have found that might be
applicable.
http://www.iptel-now.de/HOWTO/PIC/pic.html
Ed
This too is a good idea. Like money one cannot have too much
information.
One thing learned a long time ago about dedicated applications
of computers is the visual output is extremely important and
probably 80% of the total solution.
Back in the early days personal computers started with
40 character by 25 line black and white displays. Since
that time we have come a long way with 1284 by 1024 pixel
19 inch monitors with 16 million color displays. In the
mean time we have suffered much grief because programs
have had to be rewritten over and over again to meet
the specifications of the vastly improved displays.
If one is expending a lot of time, money and design
effort on a dedicated computer application it pays big
future dividends when it becomes time to add more and more
features as the market will demand. If one does not plan ahead for
an expanded display one will be doomed to redesign the hardware
and reprogram the software over and over again.
A common serial interface is a good way to go as the engine data
could ultimately be sent to a another computer with a 15 inch color
active matrix LCD located in the instrument panel.
That computer can also function as a data logger
by merely storing the display information periodically.
No extra hardware or work on your part Ed.
The down side is that computer must be programed to
format, store and display the data. This I think is a minor
problem as it can be done in visual basic or some such.
A display update rate faster than once per half second is useless
anyway as all the human eye will see is a blur. That is
plenty of time for the display computer to format and store
the data.
Paul Lamar
The AirCraft Rotary Engine NewsLetter. Powered by Linux.
ACRE NL web site. http://home.earthlink.net/~rotaryeng/
Copyright 1998-2002 All world wide rights reserved.