A basic acquisition program allows capturing all data received on a bus. In some cases, it is necessary to start capturing the traffic only when a specific event is detected. In this case, the acquisition triggering service can be used for this. Two types of event are supported: trigger on a specific ASYNC data word content and trigger on the running state of another channel.

When an acquisition with trigger is started, the received data is not available to the application until the trigger condition(s) are met. In this state, the data received is kept in a circular queue. The maximum number of data records to be kept in the queue is configurable. If the queue is full, the older data are flushed to make place for newly incoming data. When the trigger conditions are realized, the acquisition goes into running state. In this state, the pre-trig data and all newly incoming data are queued until the application reads them (through the mxfASYNCEHRxAcqRead() function).
The conditions of the condition list can either be "ANDed" or "ORed" together.

Acquisition Trigger Service

The following functions are defined for the trigger service: