Hp 3000 Series Iii Computer System Hard\Llare Organization - HP 3000 III Series Manual

System/CPU Overview
M
-CBanksO·7
U
Lower Memory Module
M
_ C Banks8·15
U
Upper Memory Module
Interactive Terrr.inal3
(Up to 16 terminals per controller)
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Central
Processing
Unit
CPU
Input/Output
Processor
lOP
Multiplexer
Channel
Device
Controller
Multiplexer
Channel Bus
De.... ice
Controller
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, Up to 15 I
, additional I
device
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controllns I
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lOP BUS
Asynchronous
Terrrinal
Controllsr
Asynchronous
Terrri"al
Controller
Port
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Selector
Controller Channel
Selector Channel Bus
Note: Each device controller on
the Multiplexer Channel can
have from 1 to 8 devices
connected to it depending
on the type of device.
Figure 2-1.
HP 3000 Series III Computer System Hardware
Organiza tion
2-4. lOP BUS. The lOP Bus provides the means for the lOP to
send control signals and control words to any Device Controller
and for the lOP to accept interrupts from any Device Controller.
(For multiplexed I/O.devices, all data transmissions also occur
via the lOP Bus. For high-speed devices connected to the Selec-
tor Channel Bus, data transmissions for direct I/O instructions
also occur via the lOP Bus.) This bus consists of a 50-conductor
flat cable and connectors and connects the lOP to every Device
Controller and Multiplexer Channel in the computer system.
2-5. SELECTOR CHANNEL BUS. The Selector Channel Bus (one for
each Selector Channel) provides the communica tion path for the
Selector Channel to select one of up to eight I/O devices for
transmission. Data transmissions on the Selector Channel Bus,
occuring as a result of an SIO instruction, are by block transfer
(data burst). This bus consists of a 50-conductor flat cable and
connectors and connects a Selector Channel to each of its as-
sociated high-speed Device Controllers.
2-2