Flachmann und Heggelbacher Docklight V2.2, User Manual

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Docklight V2.2 User Manual 07/2016 Copyright 2016 Flachmann und Heggelbacher GbR
Working with Docklight (Advanced)
6.7 Setting and Detecting a "Break" State
Some serial application protocols (e.g. LIN ) make use of the so-called Break state for
synchronization purposes. Docklight Scripting supports sending a "break" within a Send
Sequence and detecting a "break" state using a Receive Sequence definition. "break"
signals are added to your sequence definition by inserting a Function Character
'%' (F10 key) . A Docklight "break" signal has a minimum length of 15 * <nominal bit
length>.
Preconditions
·
Docklight is ready to run a test as described in testing a serial device or a protocol
implementation .
·
The Docklight project already contains one or several Send Sequences , but signalling
or detecting a "break" state is also required.
Sending a "Break" state
We assume there is already a "Test" Send Sequence which looks like this in ASCII
mode:
T | e | s | t
1. Open the Edit Send Sequence dialog .
2. Insert a "Break" function character at the beginning: Press F10 , or open the context
menu using the right mouse button , and choose Function character '%' (break
signal) . The example sequence now reads:
% | T | e | s | t
3. Click OK to confirm the changes
4. Send the test sequence using the Send button.
The TX line will go to Space (logical 0) for at least 15 bit durations, then the "Test" ASCII
sequence will be transmitted. The "break" character does not appear in the
communication window display.
Detecting a "Break" state
Received "break" signals are not displayed in the communication window, because they
are not part of the actual data sequence. Nonetheless, it is possible to define a
Receive
Sequence including a "break" function character.
1. Create a new Receive Sequence . Enter a Name for the sequence.
2. Add a Function character '%' (break signal) for the Sequence data.
3. Enter a Receive Sequence Action , for example printing the comment "BREAK
detected"
4. Click OK to confirm the changes
5. Start communications.
Docklight will now add
BREAK detected
to the communication window display each
time a break signal is detected.
NOTE: After detecting a break signal, an additional <NUL> character (decimal code 0)
may appear in the received data stream. This behavior cannot be controlled by
Docklight, it depends on how the serial
UART of your PC's COM port interpretes the
break state.