Re: Sharing memory

On Mar 8, 9:13 am, "eromlignod" <eromlig...@xxxxxxx> wrote:
Hi guys:

I'm an ME and I have an application where I'd like to use two Basic
Stamp microcontrollers working together. One is the main processor
that runs the show and does calculations; the other is a dedicated
slave that constantly distributes a series of 16-bit numbers to
various devices in a continuous, timed loop. The first processor
calculates what these numbers are based on feedback sources.

The reason I use a dedicated second processor is that its stream of
numbers can't be interrupted...it has to provide a continuous series
of values on a clock. The problem is that I can't even interrupt it
long enough to pass numbers to it from the other processor without
messing up the sequence.

What I'd like to try (if possible) is to share the same memory between
the two MCU's. So the first Basic Stamp is calculating values and
storing them to memory and the second Basic Stamp is using them as if
they were in its own memory bank simply by referring to a value by
variable name (or address??...I don't know).

Is this possible and, if so, what would be a good way of going about
it? I'm also open to alternate suggestions to solve the problem
including using a different processor (I would like to avoid investing
in another development kit or chip burner if possible though).

Thanks for any help you can provide.

Don

Hi, Don. I'm guessing from the description of your problem that
you're using two BS2-ICs, which have 16 I/O pins. You might want to
look into the Parallax BS2p40-IC. It has 32 I/O pins, and runs at the
same clock speeed as the BS2. This will allow you to retain nearly
all of your investment in programming and debug time, and you can
duplicate your BS2 development board for the BS2p40-IC with little
effort. This way you can output your 16-bit number and do everything
you're doing now with almost no changes (except you'll have time to
relax for a change).

The Basic Stamp isn't set up to share memory -- the serial EEPROM is
meant to store the tokenized program, which needs to be continuously
accessed. Any external memory is going to be an I/O hog, unless you
use serial. If you are spending time bit-banging an external serial
EEPROM from I/O pins in Stamp BASIC, not to mention arbitrating
between two Stamps, your already slow setup will get even more bogged
down.

Good luck, and feel free to post again if this isn't satisfactory --
there are many other solutions, depending on the specifics of your
problem. If you decide to post again, please include some specifics
-- such as which Stamp you're using, how many I/O you need, and a
sense of what you're doing with your project.

Chris

.

Relevant Pages

  • Re: Sharing memory
    ... Stamp microcontrollers working together. ... that runs the show and does calculations; ... What I'd like to try is to share the same memory between ... the next item of data is waiting for the slave to pick it up. ...
    (sci.electronics.basics)
  • Re: Sharing memory
    ... Stamp microcontrollers working together. ... What I'd like to try is to share the same memory between ... I would implement a periodic update on a timer interrupt and make the interrupt a sufficiently high priority. ... I can understand why you would want to avoid the costs associated with different development kits, programmers, and the increased learning curve. ...
    (sci.electronics.basics)
  • Sharing memory
    ... Stamp microcontrollers working together. ... The reason I use a dedicated second processor is that its stream of ... What I'd like to try is to share the same memory between ... So the first Basic Stamp is calculating values and ...
    (sci.electronics.basics)
  • Re: Will Digitals abandonned software ever go "public" ?
    ... common, Cutler was absolutely brutal about it. ... DuPont to do RSX-11M, the small memory version of RSX, and he inspected ... (He had a stamp that said, "Size is the Goal," but I ... I think that coding this tight is one thing that makes ...
    (comp.os.vms)