Interesting response.
I routinely implement large systems on the 8051 chip in assembly language
which I can write faster than Pascal. Assembly is a minimum of 500%
faster than
C on the 8051. I hate C anyway.
The machine is a pick & place machine designed to assemble SMT
circuit boards. It was originally controlled by a Borland Basic program
written in
Japan without any useful comments. With 5 or 6 statements per line
without even
a single space it looked like Japanese to me. Initially I needed to fix
a few bugs
and add a few features so I studied the code for while - all 100K
statements of it.
I decided rewriting it from scratch would be faster that figuring it
out. In exactly 2 weeks
I had replicated and enhanced the original functionality with 3K lines
of Pascal. I still
had to study the code to figure out how drive their special hardware,
but over the years
all of it has been replaced with simpler stuff. Numerous enhancements have
swelled the code to 8K lines using less than 2 64K blocks of memory.
The before/after size ratio shows how poorly the basic was done.
As implemented in BP it works very well. The multi-tasking part handles
functions that are not time critical, operating air cylinders that don't
know what a mSec
is. The fast motion is handled independently by Animatics Smart motors.
I have never explored the multimedia timers. I drive the LPT int to get
my own periodic
interrupt because the multi-task code already uses the timer. As you
know there are 3
timers in the timer chip but only one will generate an interrupt.
One problem I have yet to solve is the BP IDE when it hits a breakpoint
kills my LPT interrupt.
Nothing but an IDE restart will restore it. It sure cramps your
debugging style.
Thanks for your ideas.
JY
Jeff Wormsley wrote:
John Youngquist wrote:
I would like to port the program as is, but eventually get a PCI 48
I/O line card to escape
the ISA bus and also talk USB as well. Getting it to run on later
versions of Windows might
be useful. This program controls a machine on a single purpose
computer. Windows is used
to handle files, networks, and little else. Most of the time only
this program is run. A port to
Linux might be acceptable if that would solve some problems.
Are these insurmountable obstacles?
Probably not if you're willing to spend a ton of time and money, but
you might be better off moving the bulk of this system off of a PC and
on to a dedicated micro controller board, and just using a PC to
handle UI and files/network and things that don't have any real time
requirements. The STM-32 Cortex chips in the 144 pin package should
probably have enough I/O and speed to do what you want, with built in
ram/rom. Coupled with FreeRTOS, you can have a quite capable system
for not a lot of money (you should be able to build a board to replace
the PC hardware for a couple of hundred dollars, depending on how
sophisticated the 48 port I/O board is).
I'm surprised the current system ran properly on a Win98 DOS box,
considering how badly Windows messes up real time (those 10ms breaks
should have probably been much longer on occasion when the Windows
kernel was busy doing stuff with interrupts disabled). Until I found
out how to use the multimedia timers, I couldn't get better than 55ms
response out of Windows, even from a DOS box.
Jeff.
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