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CT19901 Schematic ( PDF Datasheet ) - Aeroflex Circuit Technology

Teilenummer CT19901
Beschreibung MIL-STD-1553B Remote Terminal/ Bus Controller/ or Passive Monitor Hybrid with Status Word Control
Hersteller Aeroflex Circuit Technology
Logo Aeroflex Circuit Technology Logo 




Gesamt 29 Seiten
CT19901 Datasheet, Funktion
CT1990/1 Series
MIL-STD-1553B Remote Terminal, Bus Controller,
or Passive Monitor Hybrid with Status Word Control
Features
• Performs the Complete Dual-Redundant Remote Terminal, Bus Controller Protocol
and Passive Monitor Functions of MIL-STD-1553B
• Automated Self-Test Functions
• Allows setting of the Message Error Bit on illegal commands
• Provides programmable control over Terminal Flag and Subsystem Flag Status Bits
• MIL-PRF-38534 Compliant Circuits Available
• 50 mw Typical Power Consumption
• Small Size
• Available in Ceramic Plug-in Package Configuration
• Compatible with all ACT Driver/Receiver Units
CIRCUIT TECHNOLOGY
• 5V DC Operation
• Full Military (-55°C to +125°C) Temperature Range
• DESC SMD# 5962–94775: Released CT1990, Pending CT1991
1
General Description
The CT1990/1 Series is a monolithic implementation of the MIL-STD-1553B Bus Controller, Remote
Terminal and Passive Monitor functions. All protocol functions of MIL-STD-1553B are incorporated and a
number of options are included to improve flexibility. These features include programming of the status
word, illegalizing specific commands and an independent loop back self-test which is initiated by the
subsystem. This unit is directly compatible with all transceivers and microprocessor interfaces such as the
CT1611 and CT1800 produced by Aeroflex Incorporated.
Block Diagram (With Transformers)
Encoder
Interface
Unit
Sub Address
&
Word Count
Outputs
BUS "0"
T/R
Hybrid
BUS "1"
T/R
Hybrid
Driver
Select
&
Enable
Decoder
"O"
Decoder
"1"
Status
Word
Control
Internal
Highway
Control
Program
Inputs
Discrete
Outputs
Control
Inputs
Terminal
Address
Inputs
CT1990/1
eroflex Circuit Technology – Data Bus Modules For The Future © SCD1990 REV B 8/21/00






CT19901 Datasheet, Funktion
instead of the current one, and therefore a currently set status bit will not be seen by the Bus Controller.
Therefore the user is advised to hold SERVREQ low until the requested service takes place.
Use of the Subsystem Status Bit
This status bit is used by the RT to indicate a subsystem fault condition. If the subsystem sets SSERR low at
any time, the subsystem fault condition in the RT will be set, and the Subsystem Flag status bit will subsequently
be set. The fault condition will also be set if a handshaking failure takes place during a data transfer to or from
the subsystem. The fault condition is cleared on power-up or by a Reset mode command.
Dynamic Bus Control Acceptance Status Bit
DBCACC, when set true, enables an RT to configure itself into a Bus Controller, if the subsystem has the
capability, by allowing DBCREQ to pulse true and BIT TIME 18 to be set in the status response. If Dynamic Bus
Control is not required then DBCACC must be tied high. DBCACC tied high inhibits DBCREQ and clears BIT
TIME 18 in the status response.
OPTIONAL STATUS WORD CONTROL
Message Error Bit
The CT1990/1 monitors all receptions for errors and sets the Message Error Bit as prescribed in
MIL-STD-1553B. The subsystem designer may, however, exercise the option of monitoring for illegal commands
and forcing the Message Error Bit to be set.
The word count and subaddress lines for the current command are valid when INCMD goes low. The subsystem
must then determine whether or not the word count or subaddress is to be considered illegal by the RT. If either
of them is considered illegal, the subsystem must produce a positive-going pulse called MEREQ. The
positive-going edge of MEREQ must occur within 500 ns of the falling edge of INCMD .
Subsystem Flag and Terminal Flag Bits
The conditions that cause the Subsystem Flag and Terminal Flag Bits in the Status Word to be reset may be
controlled by the subsystem using the ENABLE, BIT DECODE, NEXT STATUS, and STATUS UPDATE inputs. If
ENABLE is inactive (high), then the Terminal Flag and Subsystem Flag behavior is the same as described
below: (i.e. the other three option lines are disabled).
Subsystem Flag Bit
This bit is reset to logic zero by a power up initialization or the servicing of a legal mode command to reset
the remote terminal (code 01000).
This bit shall be set in the current status register if the subsystem error line, SSERR, from the subsystem
ever goes active low. This bit shall also be set if an RT/subsystem handshaking failure occurs. This bit,
once set, shall be repeatedly set until the detected error condition is known to be no longer present.
Terminal Flag Bit
This bit is reset to logic zero by a power up initialization or the servicing of a legal mode command to reset
the remote terminal (code 01000). This bit can be set to logic one in the current status register in four
possible ways:
a) If the RX detects any message encoding error in the terminals transmission. A loop test failure,
LTFAIL, will be signalled which shall cause the Terminal Flag to be set and the transmission aborted.
b) If a transmitter timeout occurs while the terminal is transmitting.
c) If a remote terminal self test fails.
d) If there is a parity error in the hard wired address to the RX chip.
This bit, once set, shall be repeatedly set until the detected error condition is known to be no longer
present. The transmission of this bit as a logic one can be inhibited a legal mode command to inhibit
terminal flag bit (code 00110). Similarly, this inhibit can be removed by a mode command to override inhibit
terminal flag bit (code 00111), a power up initialization or a legal mode command to reset remote terminal
(code 01000).
Aeroflex Circuit Technology
6 SCDCT1990 REV B 8/21/00 Plainview NY (516) 694-6700

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CT19901 pdf, datenblatt
Pin Description (Cont.)
Signal
Direction
Signal Description
STATEN/
STATSTB
STAT UPDATE
BITEN/
RMDSTB
DWSYNC
ENABLE
CMSYNC
NDRQ
NEXT STAT
PASMON
BCOPSTB
RMDSTB
BCOPA
BCOPB
REQBUS A
REQBUS B
OUTPUT
INPUT
OUTPUT
OUTPUT
INPUT
OUTPUT
OUTPUT
INPUT
INPUT
INPUT
INPUT
INPUT
BI-DIRECTIONAL
BI-DIRECTIONAL
Status Enable/Status Strobe - This line pulses low to enable the status word
onto the internal highway for transmission. When in RT mode this line must not
be used to enable data from the subsystem. This line also pulses high, when in
the Bus Control mode, to strobe received status words into the subsystem.
When PASMON is true this line pulses high for Command and Status words.
Status Update - When held low, causes TF or SSF to appear in Status Word
response to Transmit Status or Transmit Last Command issued immediately
after fault occurrence
Built In Test Enable/Receive Mode Data Strobe - This line pulses low when
servicing a valid and legal mode command to transmit the internal BIT word.
This signal is for information only and must not be used to enable data from the
subsystem. This line also pulses high when in the Bus Control mode when
mode data is received to be passed to the subsystem and when data is passed
to the subsystem during PASMON.
Data Word Sync - This line goes low if a data word sync and two Manchester
biphase bits are valid. CT1990 only.
Enable - When held low, enables Bit Decode, Next Status, and Status Update
program lines.
Command Word Sync - This line goes low if a command word sync and two
Manchester biphase bits are valid. CT1990 only.
No Data Required - This line goes low if the encoder transmit buffer is full i.e.
another word is going to be transmitted. This signal is for information only and
must not be used to enable data from the subsystem.
Next Status - When held low, causes TF or SSF to appear in very next Status
Word after fault occurrence (except for Transmit Status or Transmit Last Com-
mand).
Passive Monitor - When functioning as a Bus Controller this line acts as a
passive monitor select. The active going edge of this line will cause the
REQBUS lines to be latched and that bus, now selected will be monitored so
long as PASMON remains low. All traffic on the bus will be handed, after
validation, to the subsystem via STATSTB for status and commands words,
and RMDSTB for data words.
Bus Controller Operation Strobe - When functioning as a Bus Controller a
low going pulse on this line will initiate the selected bus controller operation on
the requested bus, using BCOPA&B and REQBUSA&B.
See BITEN/RMDSTB.
Bus Control Operation A - Least significant bit of the bus controller operation
select lines.
Bus Control Operation B - Most significant bit of the bus controller operation
select lines.
Request Bus A - This line, when in RT mode, is the least significant bit of the
bus request lines which specify the origin of the command, i.e. they are
sources. When in BC mode these lines are sinks and specify which bus is to be
used for the next command.
Request Bus B - Most significant bit of the bus request lines. (See above for
description.)
Aeroflex Circuit Technology
12 SCDCT1990 REV B 8/21/00 Plainview NY (516) 694-6700

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