The triggering of FERA ADCs

The figure 1.1 shows the actions taken by the ancillary trigger to start the coding of the FERA ADcs.

  
Figure 1.1: block diagram of the ancillary trigger

To start a FERA coding, the ancillary trigger is in agreement with the followings rules:

1. must detect a Raw Particule from ancillary detectors.
2. must check if a Fast Trigger from Master Trigger is received.
3. can wait for a Fast trigger if the previous rule is false.
4. must open the analog gates and strechers for the FERA ADCs.

During the analog processing, the ancillary trigger is in agreement with the followings rules:

1. must check a pileup and assert a reject signal if true.
2. must receive an inhibit signal to discard new Raw Particule or Fast Trigger.

On completion of the coding, the Ancillary trigger is in agreement with the followings rules:

1. must Clear its internal logic after FERA readout.
2. must know if a Fast Trigger from master trigger is occured.
3. must know if a Valid from master trigger is occured.

At any time, the ancillary trigger must also know if:

1. the Euroball is working or not via the GO*/STOP line.
2. the FERA readout is completed or aborted via TIMEOUT.

the timing constraints for the ancillary trigger and the master trigger are described in the next section.