Hardware for PHOBOS Trigger Control

Minutes from the fall 98 DAQ meetings:

• TOF crate will always be running in the single event mode

• Silicon crate may pipeline several (4?) events in the internal buffers

List of the VME modules required for implementation of the trigger control and event builder synchronization:

• Event Number Generator, ENG, located in one (master) of the VME crates. It generates Event#&Type .

• Interface to ENG, ING, located in all VME crates. It receives Event#&Type from the ENG.

• Trigger Registers, TR, located in the Trigger VME crate. It latches current trigger conditions.

• Enable Registers, ER, located in the Trigger VME crate. It enables/disables different trigger sources.

• Programmable Prescalers, 1/n, located in the Trigger VME crate.

Using programmable logic devices like ispLSI from LATTICE it is possible to incorporate the functionality of the ENG, ING, TR, ER (and, possibly, 1/n) inside single module.

Let’s call it PCD (Programmable Control and Data ports). Each crate will have several PCD modules configured in different ways. For example in the Trigger crate it will be one PCD configured as ING, and several PCDs - as ER/TR.

The advantage of using ispLSI:

• In-field programming

• Definite delay

• 3-year experience

CIn

Control Input Port

COut

Control Input Port

DIO

Data In/Out Port

dECL

dECL

dTTL

Functional diagram of the PCD

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