External triggers originate from the external trigger line. Pulling this line to zero causes the board to change its state to Run. The external trigger line overrides other trigger conditions set for the GT-DIO board.
It is also possible to set a conditional trigger command, which is activated upon receiving external event input lines. This external event may be any expected value on all or part of the external event input lines. The 16 external event lines are ANDed with pre-defined masks and compared with pre-defined events in registers D and T.
The external events trigger function is shown in the figure below:
External Events Trigger Block Diagram
The external events trigger can be set to one or two levels. In the one level mode, the trigger will be generated after the external condition has been met with the D or T event mask registers. In the two level mode, the board will wait for two sequential events to be met before issuing the trigger signal (D first, T second or opposite).