Chapter 3 Hardware Installation

Step 2: Jumpers and Termination

Page 3 - 7

Bus Request/ Grant Jumper

This jumper block is used to select the level at which the RF3880 adapter can request and be granted access to the VMEbus by the ARBITER. The four sets of Bus Request and Grant signals are daisy-chained separately on the VMEbus backplane. Only one of the four levels can be used by a single REQUESTER. The Bus Grant signals that are not used are passed through to the next board on the backplane. The Bus Grant signal will be gated on the adapter for whichever level you choose. If the RF3880 adapter has a request for the bus pending, it will take control of the VMEbus. If it has no request pending it will pass the Bus Grant signal to the next board. The Bus Request/Grant jumper block is illustrated below.

Figure 5 Bus Request/Grant and Sysfail Jumpers

The setting shown in the above figure is the default from the factory. It indicates level 3 for Bus Request/Grant.

To select a Bus Request/Grant level, place three jumpers down the level you wish to use. The unused levels should have jumpers placed from pin 4 to 5.

Figure 6 Bus Request and Grant on Level 2

Figure 7 Bus Request and Grant on Level 1

User’s Guide

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Ciprico Rimfire 3880 manual Bus Request/ Grant Jumper, Bus Request/Grant and Sysfail Jumpers