Chapter 3: Functional Description; Hardware Overview; Processor Board; Meillory - HP 340 Series Service Manual

Functional Description
Hardware Overview
Figure 3-1 is a block diagram of the SPU.
+5
Power
-12
Supply
+12
Processor
Board
Backplane
RAM
LAN
Video/Graphics
Board
010-1 Slot
3
Video/Graphics
010-1 Accessory Card
Figure 3-1. SPU Block Diagram
Processor Board
In the Model 340's SPU a processor board much like the Model 360's is used. It's major
differences are that several interface circuits are used. A RAM controller circuit is used to
manage up to four RAM array boards that connect into the processor board.
A 32-bit I/O bus interfaces this board with the add-on memory, video/graphics, and on-board
interfaces. Two Boot ROMs and self-test LEDs comprise the fundamental hardware to self-test
the SPU hardware and boot the operating system. DIO-I accessory cards are interfaced with a
16-bit bus.
Memory
Up to 16 Mbytes of parity RAM is supported. Each RAM board has 4 Mbytes and are
autoconfiguring. Additional memory is available as an HP 98268A 4 Mbyte RAM Board
Upgrade.
Functional Description
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