Good ideas. The only problem with a laptop is that there is no 16 or
32 channel (or any?) A/D cards for them. That's why I'm trying to work
a PC mobo solution.
AI Nut
I would not exactly say that. Get a subscription to Nuts and Volts.
subscrib@nutsvolts.com
http://www.nutsvolts.com
There are companies that sell data acq boards with RS232 output.
Paul Lamar
Yes, I've seen their ads and webpages, but I'm a bit concerned about
missing critical data points when all those channels (18-24 for me) are
being stuffed down a low speed pipe at 9600 and even 4800 baud. Even if
you only sample each channel once per second, you start getting into the
fuzzy Nyquist realms at those low baud rates. The cpu will be spending
an inordinate amount of time servicing the serial port instead of
massaging and displaying the data. There is enough bandwidth even in a
P166, but that wouldn't leave enough headroom to give me a high
confidence level. Guess I like to over-engineer things 8-).
AI Nut
Once a second is a bit high for engine monitoring updates on digital instruments.
As I recall the least significant digit jitters so it is a bit distracting.
You need to simulate this on your computer monitor and check. As I recall
once every two or three seconds works better.
DOS QB can read that port in just a few micro seconds if you use
the QB ON COM hardware interrupt capabilities. The the UART does the actual serial
low level bit banging and it stores the data in a 16 byte hardware on chip
buffer as I recall. Microshit Windows on the other hand cannot service hard ware
interrupts in real time as I under stand it.
This means the QB program has plenty of time to do processing between
serial port hardware interrupts. I used this in my moving map program and it
worked great getting GPS updates every one second with a lowly
386SX mother board running at 33 to 66 MHZ as I recall.
For more on multi-tasking using hardware interrupts see my IEEE
paper. This system would service eight functions with a one MHZ 6502
in real time using eight hardware interrupts.
Microprocessor-Based System for Roll-Down and Acceleration Tests
by D.K. Lynn, C.R. Derouin, and Paul Lamar
Los Alamos Scientific Laboratory
Published in IEEE Proceedings 29th Vehicular Technology Conference
(The technical details of the road test system.)
Arlington, Illinois, March 28-30, 1979
As I said running DOS programs on a modern CPU things happen
instantaneously. Greg Richter agrees with me as he has written his
own DOS like OS (or he has modified DR DOS which was available in
source code form as I recall :-)>) for his moving map stuff.
People have grown to accept and take for granted the slowness
of Microshit Windows which is a real shame. Try DOS and QB on your
new computer and you will be amazed.
Let me know if you need the QB compiler.
Paul Lamar
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