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SECTION
I
INTRODUCTION
SCOPE OF
MANUAL
This
manual
describes
the
characteristics
of the
various interfaces
between
the
Honeywell
HI
12
Controller and
customer-designed
external
equipment.
A
functional
description
is
given
for
each
method
of
HI
12
input/output with individual
requirements
specified.
Also
defined are control
lines,
timing requirements, and
interface drive
and
load
requirements.
APPLICABLE
DOCUMENTS
Title
Doc. No.
HI
12
Programmers
Reference Manual
70130072242
H112
Central
Processor
Description
70130072244
DESCRIPTION
The Honeywell H112
Controller has four types
of
input/output:
Programmed
l/O;
Load
Mode
Transfers;
Machine
Control
Interface;
and
optionally available
Direct Data Channel.
The
standard
programmed
input/output structure
in the
HI
12
is
a single cable, duplex,
"party
line"
system.
Six
l/O
instructions, plus
reassignable,
programmed
priority inter-
rupts,
make
the
controller's parallel transfer
l/O
bus capable
of a
wide
variety
of
applications.
Programmed
l/o
data transfers take place
under software
control.
The
priority inter-
rupt
line
may
be
utilized
during these transfers
to
identify
device
ready
status;
or alternately,
device
ready
status
may
be
determined by repeated
testing either
by an
SKS
command
or
by
the skip test
incorporated
into the
data transfer
instructions.
Twelve
bit
parallel
transfers
are
made
to
and
from
the
accumulator
via
the
programmed
I/O
bus.
Load
Mode
Transfers
also
occur over
the
l/O
bus
but
are
entirely
under
the
control
of
the
HI
12
hardware.
The
direction
of
load
mode
transfers
is
always
into
the controller.
The Machine
Control
Interface
makes
available certain functions
(run,
stop, load,
clear,
start,
and
single instruction execution)
to the
system, whether or
not the control
panel
is
present.
This feature allows
the
HI
12 to
operate without
the
control panel.
Using
the
plug-in panel feature
reduces
unit
cost
and prevents unauthorized personnel
from
interfering
with
HI
12
operation.
The
Direct Data Channel
option
provides an l/O
path
for
high-speed
data transfers
between
the
controller
and l/O
devices.
Transfers between
the
channel located
in
the
controller
and subchannels
located
in
the
peripheral devices
utilize
both the
programmed
1-1
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