Data Sheet

Proteus VSM
207
Do note that with constantly polling firmware such as this there is considerable overhead in
terms of performance as we are constantly writing textual data to the display. However, in most
cases you are using the instrument for testing or debugging, at which point the simulation speed
is secondary to problem solving. As with all debugging windows you can close the debugger
when not in use and then re-open it from the Debug Menu in either VSM Studio or Proteus.
Further Reading:
More information on the protocol analyser - along with other instrumentation – is available
in the Proteus VSM reference manual. In particular, note that you can use the analyser as
an I2C master (or slave) device as well as simply as a monitor.
More information on picking, placing and wiring on the schematic can be found in the
Proteus tutorial documentation, launchable from the home page.
Graph Based Measurements
We can look at the same traffic in a different way by using graph based simulation. There are
however some important differences which affect how we set up the simulation, namely:
You cannot interact with the circuit during a graph based simulation.
A graph based simulation runs for a specified period of time.
The results are not visible until this period of time has finished and the simulation has
stopped.
Given the above, let's look at how we might analyse the I2C traffic with a digital graph. First of
all, delete the interactive I2C debugger by right clicking on it and selecting delete from the
context menu.
Next, make some space for the graph by dragging a tagbox around the display and wires with
the right mouse button so that they all highlight. Left depress the mouse and drag the lot to the
right of the schematic.