Data Sheet

Proteus VSM
203
This time when we run the simulation the breakpoint will not trigger until we press the mode
selection button to enter temperature mode (where temperature is transmitted on the I2C bus).
You should find that you end up inside one of the I2C routines in the source code. You can
follow the code path from here using the stepping and debugging described in previous
sections. Stop the simulation again when you are finished.
Interactive Measurements
It is quite common to want to examine signals and waveforms on the design and Proteus
provides two main ways of doing this. As an example, let's assume we need to examine the I2C
traffic from the MCP9800 temperature sensor; we can do this either interactively or by more
traditional graph based methods.
The first thing we need to do is tidy up the schematic and remove the debugging items we have
used previously. You can remove the voltage probe by right clicking on the probe on the
schematic and selecting delete from the context menu. Similarly, we can right click on the
border of the active popup objects and delete them.
When an active popup is defined on the schematic Proteus will switch to VSM
Studio when the simulation starts as it is assumed you are primarily debugging
source code. Since we are now analyzing signals we want to remove the active
popups so that the simulation starts with the schematic tab open.
The next thing to do is to get the I2C debugger placed and connected. Select the instrument
icon which produces a list of available interactive measurement tools in the parts bin. In our
case, the obvious candidate is the I2C protocol analyser.