I/O Data Routes - HP 3000 III Series Manual

I/O System
SELECTOR CHANNEL BUS
_--r--...
High Speed
Device
I
o
P
System
Clock
Direct
"""""'--~
I/O
Data
CENTRAL,(CTL) DATA BUS
lOP BUS
DIRECT I/O DATA
r--- - -- -
-D~ct1
I/O
I
Device
I
I I
I
I
I
DIRECT I/O DEVICE
I
L
CONTROLLE~
--l
*
PORT 2 NOT AVAI lABlE FOR USE.
MULTIPLEXED
SIO DATA
MUX CHANNEL BUS
Figure 7-12. I/O Da ta Routes
7-25. I/O Data Routes
Data transfer routes for both low- and high-speed devices and
direct I/O are shown in figure 7-12. At least one of each type
of unit (two low-speed Device Controllers, one high-speed Device
Controller, one MUltiplexer Channel, two memory modules, etc.) is
shown. The routes shown in figure 7-12 are the normal input/
ou tput data routes.
For direct I/O instructions to a Multiplexer Channel device, in-
formation is transferred to or from the TOS in the CPU via the
lOP and lOP Bus. The information could be device status (for TIO
or rejected SIO, RIO, or WIO), control information (CIO), or data
(RIO or WIO). For SIO operation, data is transferred to and from
memory via the CTL Bus, lOP, and lOP Bus.
For direct I/O instructions to a Selector Channel device, the
data route is the same as for a Multiplexer Channel device; to or
from the TOS in the CPU via the lOP and lOP Bus. For SIO opera-
tion, data is transferred to and from memory via the CTL Bus,
Port Controller, Selector Channel, and Selector Channel Bus.
7-22