gnupic: Programmable stimuli for gpsim?
Subject:
Programmable stimuli for gpsim?
From:
Federico Heinz ####@####.####
Date:
15 Dec 2002 15:10:24 -0000
Message-Id: <1039962209.913.63.camel@michelle>
Folks,
I've been looking at gpsim, and it's a great piece of software! So far,
I had followed my old dinosaur instict and done my debugging with
blinking LEDs, but this is much better.
For my project, however, the waveform stimuli provided by the program
are insufficient, since I must be able to simulate interaction with a
host processor (i.e. I'll need the stimuli not just to monkey a signal,
but the signal must be determined at run time, as it encodes commands
and responses from the host). Is there a way to attach an external
program to a collection of pins? It looks like it ought to be doable via
modules, but I'm not familiar with gpsim's internals (yet?) as to figure
out how it ought to be done.
If I'm not being clear as to what I mean, the general idea would be to
enable a filter-like program (i.e. one that reads from STDIN and writes
to STDOUT), which would be called from within gpsim. Communication with
the program would be via a simple ASCII-based protocol:
* The program initializes, and prints a ready message which contains the
protocol version number.
* Gpsim answers with an ACK, stating its own version.
* The program sends a message (or series of messages) stating how many
pins the component it simulates has, how they are called, and their
initial I/O configuration
* From then on, gpsim tracks the signals connected to the program's
"input pins", and sends a signal update together with a clock timestamp
to the program each time any one of them changes, which the program
ACKs.
* Similarly, each time the computation of the value at one of the PIC's
input pins involves one of the program's outputs, a status query is sent
to the program, again together with a clock timestamp, to which the
program reports the value of all its output pins.
* Both the program's ACKs to signal updates and the signal reports from
the program would include syntax to optionally reconfigure its pins
(turn inputs into outputs, and viceversa).
Is this possible now, and it's just not documented? If not, could this
make it into the wish list?
Fede
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