Fccc Board; Llm Board - Texas Instruments 990 User Manual
Dx10 hdlc communications package
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Also See for 990:
- Operation manual (276 pages) ,
- Manual (211 pages) ,
- Installation and operation manual (122 pages)
Table of Contents
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Introduction
FCCC Board.
Master
control
of
the
FCCC board, and consequently of level 1
communications, is provided by a TMS 9900
microprocessor.
Both
RAM
and
ROM are with the TMS 9900 and serve both as a source of
commands for the four TMS 9903 communications controllers on
the
board
and
as
storage
for
part
of
the
HDLC
software.
The
communications controllers take the data to
be
transmitted
and
convert
it
to
the serial bit streams necessary for feeding the
physical communications lines.
Drivers associated with each of the four TMS
9903s
provide
the
appropriate
line
signals
to
the
corresponding communications
channel connector located on the outer edge of
the
FCCC
board.
The
communications
lines
connect
to
the
four communications
channel connectors.
Selection of either
the
EIA
RS-232-C
(or
423) or differential drive option is accomplished by reconnecting
to
the
proper
pi ns
on the connectors.
No sof tware changes or
FCCC wiring changes are
re~ired
to
change
a
line
from
the
di ff erenti al mode to an E IA mode.
Several
presetting
operations,
including
the
allocation of a
TILINE address, are
re~i
red on the FCCC board to allow operation
as a pr imar y st ation in an
HDLC
networ k.
Ref er
to
the
FCCC
Installation and Operation Manual
for
complete
instructions on
all FCCC options that can be preset.
LLM Board.
Different types of secondary stations can be used in addition
to
the
TX5,
as shown in Figure 1-5.
However, this manual concerns
itself mainly with the TX5 secondary station
e~ipped
with
the
local-line
module
(LLM).
For a discussion of the operation of
other types of
secondary
stations,
refer
to
the
appropriate
manual.
The
LLM provides only one communication line connection and uses
the TMS 9980 microprocessor for
control,
as
well
as
a
small
amount
of
roM
and RAM.
Canpared to the FCCC board, the LLM is
considerably more dependent on main memory software
support
and
connects
to
the
computer"'s
CRU
instead
of
the
TILINE bus.
However, the LLM contains the same drivers and receivers
as
the
FCCC
board,
and
it
therefore
supports
the
same
local-line
interface.
A modem option is also available.
Two switch settings must be made on
the
LLM
board
for
it
to
function
correctly
wi th
the communications system.
One is the
data rate switch; the other is the address switch.
The
address
swi tch
must
be
set to the secondary address of the TX5 secondary
station.
Jumper connections must also be made.
Ref er to Section
3 of
this
manual
and
to
the
Local Line Module Operation and
Maintenance Manual for further information on required settings.
2270526-9701
1-15
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