The start-of-scan and end-of-scan trigger synchronization mechanism ensures that all the cards of the DF-chain capture the same lines of image data.
Data Forwarding - Master Card
In a DF-chain, the DF-master card forwards its start-of-scan and end-of-scan events to the DF-slave cards.
The generation of the start-of-scan and end-of-scan events on the DF-master is achieved in the same way as for non-data-forwarding Coaxlink cards.
See also: Line Scan Acquisition
The DF-master card:
| ● | First, synchronizes the asynchronous scan triggers on the next start-of line image data. |
| ● | Then, share the synchronized scan triggers with all the DF-slaves. |
The sharing of the scan triggers is achieved by the insertion of high-priority "custom GPIO messages" in the bit stream. These messages are forwarded by all the DF-slaves together with the image data.
Data Forwarding - Slave Card(s)
On reception of such a message, the DF-slave generates a hardware event. Two kind of events are possible:
| ● | Start-of-scan event. |
| ● | End-of-scan event |
These events are available through the Event Input Tool of the I/O Toolbox.
For applications requiring synchronized line-scan acquisition, the I/O toolbox EIN tools of the DF-slaves must be used as local start-of-scan and end-of-scan trigger sources.