Ciprico Rimfire 3880 User Manual download pdf (Page 27)

User’s Guide 21020285 D

Chapter 2 Hardware Essentials

Hardware Structure and Description Page 2 - 3

Hardware

Structure and

Description

The RF3880 hardware design incorporates the technology available from the

following components:

• Intel 20 MHz 80186XL microprocessor

• QLogic FAS256 16-bit, Fast SCSI Controller chip

• High Density Programmable Logic Devices (PLD’s) for VMEbus, and

buffer control

• Ciprico Pipelined System Interface (PSI)

Intel 80186XL

At the core of the RF3880 design is the 80186XL supervisory microprocessor.

The 80186 is well suited to the task of overseeing board operations; it uses

optimized instruction encoding for high performance and memory efficiency.

RF3880 performance is further boosted by using the 20 MHz version of the

80186.

QLogic

FAS 256

SCSI bus protocol for the RF3880 is efficiently handled by the QLogic Fast

SCSI chip. The QLogic chip provides the capability for 16-bit transfers on the

SCSI bus, as well as negotiation for Fast Synchronous transfers across the bus,

up to 20 MB/s. The QLogic FAS256 chip is a registered device that can be set-

up for automated bus operations. These options are available to you via the

Board-control commands discussed in Chapter 7.

Pipelined

System

Interface

Ciprico created the custom VLSI Pipelined System Interface (PSI) to

coordinate access to the system address bus; it has registers for the DMA

address count and transfer count. Also contained in the chip are the Channel

Attention port register and the Interrupt Request level register.

Data Buffer

Using high-speed video DRAMs to provide 512 Kbytes of buffer space with

hardware control logic, the RF3880 creates a data buffer that adjusts

dynamically to the type and size of the data transfers involved. Performed in

hardware, this design maximizes performance by bypassing the need for

microprocessor involvement.

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Ciprico Rimfire 3880 User Manual Page 27