Page E - 6

How to

Maximize

Performance

Appendix E Design Differences

How to Maximize Performance

Uniquely Identify the RF3880

In order to differentiate the RF3880 from the RF3560/70 and RF3870, a new word field was added to the Board Information Data Structure returned from the Board Information command. This new word is the Adapter Base Model # (number) word.

Odd-byte Addressing

VME addresses for transfers must be word-aligned.

In order to take full advantage of the RF3880 design, you should do the following:

Align VME D64 data buffers to 2K address boundaries, and specify a Bus Throttle of 2048 bytes per burst. Any other alignment will reduce the maximum Burst size to 256 bytes per burst.

Align all data buffers to double-longword address boundaries. Any other alignment will cause multiple data transfer cycles on the VME bus. The first transfer will move enough data to align the address to a double- longword. The next transfer will move the data according to the Bus Throttle setting.

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User’s Guide

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Ciprico Rimfire 3880 manual How to Maximize Performance, Odd-byte Addressing