Timing diagram
A timing diagram represents the instants of the events occurrences and the associated managers states evolutions. Timing diagrams exist in two flavors in the MultiCam model.
A manager timing diagram only represents the events and states belonging to one manager. A MultiCam timing diagram represents several events and several managers states of the MultiCam block diagram, it shows the evolution of the MultiCam model.
For the example sake, the figure below shows one possible MultiCam timing diagram for an area-scan camera. The activity consists of two sequences, the sequence consists of two phases and the phase is made of two slices.
The figure shows the propagation of the trigger event. The trigger principle is very simple: each trigger induces a slice.
The trigger effect on the phase and sequence depends on their respective states. If the sequence manager is waiting for a trigger when a trigger event occurs, the sequence starts and generates the SAS event; otherwise the sequence is not affected by the trigger. The phase manager operates in the same way.
As shown on the figure, the first trigger event generates a succession of events because all managers are waiting for a trigger event.
The second trigger event directly affects the slice manager because the phase and sequence managers are not waiting for a trigger since they are not terminated. The pre-programmed number (2) of slices and phases has not yet been reached. The completion manager monitors this pre-programmed number of phases and sequences.
The table below summarizes the events occurring during an acquisition:
|
Event |
Meaning |
|---|---|
|
EAP |
“End of Acquisition Phase”. This event is issued by the transfer manager when the filling process of the destination surface has been completed. |
|
EAS |
“End of Acquisition Sequence”. This event is issued by the transfer manager when the filling process of the last destination surface of the sequence has been completed. |
|
ET |
“End Trigger Event”. This event is issued by the trigger manager following a “Hardware End Trigger” event (HETRG) when a programmed delay has expired. |
|
HETRG |
“Hardware End Trigger”. This event is generated when a dedicated transition occurs on a hardware line. |
|
HTRG |
“Hardware Trigger”. This event is generated when a dedicated transition occurs on a hardware line. |
|
ROC |
“Readout Complete”. This event is generated by the camera manager when a readout period of the camera completes. |
|
SACT |
“Set Active”. This event is issued when the user application writes ACTIVE to the ChannelState parameter. |
|
SAP |
“Start of Acquisition Phase”. This event is issued by the phase manager to notify the beginning of a new phase. |
|
SAS |
“Start of Acquisition Sequence”. This event is issued by the sequence manager to notify the beginning of a new sequence. |
|
SASL |
“Start of Acquisition Slice”. This event is issued by the slice manager to notify the beginning of a new slice. |
|
SCA |
“Start of Channel Activity”. This event is issued by the activity manager to notify the beginning of a new channel activity. |
|
STRG |
“Software Trigger”. This event is issued when the user application writes TRIG to the ForceTrig parameter. |
|
TE |
“Trigger Event”. This event is issued by the trigger manager following a “Hardware Trigger” (HTRG) or “Software Trigger” (STRG) event when a programmed delay has expired. |
|
XPC |
“Exposure Complete”. This event is issued by the camera manager when the exposure period of the camera completes. |