When monitoring serial communications between two devices, you might want to test for a rare error and the interesting parts would be just the serial communication before and after this event. You could look for this situation by logging the test and searching the log files for the characteristic error sequence. This could mean storing and analyzing several MB of data when you are actually just looking for a few bytes though, if they appeared at all. As an alternative, you can use the Snapshot feature as described below.
Preconditions
•Docklight is ready to run a test as described in the previous use cases, e.g. monitoring serial communications between two devices.
Taking a snapshot
A) Defining a trigger for the snapshot
| 1. | Define the sequence that appears in your error situation as a Receive Sequence. |
| 2. | Check the Trigger tab in the "action" part of the Receive Sequence dialog: The trigger option must be enabled if this is the sequence that you want to track down. |
NOTE: Do not forget to disable the trigger option for all other Receive Sequences that should be ignored in your test so that they do not trigger the snapshot.
B) Creating a snapshot
Click on the 
Snapshot button of the toolbar. Docklight will start communications, but will not display anything in the communication window. If the trigger sequence is detected, Docklight will display communication data before and after the trigger event. Further data is processed, until the trigger sequence is located roughly in the middle of the communication window. Docklight will then stop communication and position the cursor at the trigger sequence.