CT2565 Datasheet, PDF (16/31 Pages) Aeroflex Circuit Technology – CT2565 Bus Controller, Remote Terminal and BUS Monitor FOR MIL-STD-1553B

Use of Status Word
The status word may be captured by the
subsystem as it is transmitted to the 1553 port by
pulsing BUFENA (pin 58) low during STATEN (pin
3: 520ns low pulse). Data becomes valid
approximately 50ns after the falling edge of
BUFENA.
This corresponds with all
non-broadcast message transfers and the
TRANSMIT STATUS WORD mode command.
Note that the status word may be transmitted prior
to an error condition (See Transmit CMD). These
conditions will be indicated in the "next" status
word and may be monitored if the BC requests the
SW before it is altered (See Mode Commands).
Subsystem Control
The CT2565 allows the subsystem total control
over the status word flags using the inputs
indicated in Table 7.
BIT Word
The BIT Word (Built-In-Test) becomes available in
response to a TRANSMIT BIT WORD mode
command and provides additional status
information (See Figure 19) to that provided by the
status word. The subsystem may capture the BIT
word on the parallel data bus by pulsing BUFENA
(pin 58) low during BITEN (pin 43: approximately
520ns low pulse). Data Becomes valid
approximately 50ns after the falling edge of
BUFENA. Like the status word, the BIT word
cannot be altered by the subsystem.
PIN
#
SYMBOL
DESCRIPTION
6 DBACCEPT RT accepts BC operation
responsibility (See Table 2).
7 SSFLAG
Transmitted data may be
invalid sets SSFLAG bit.
8 SVCREQ
Service Request; see
Transmit Vector mode
command.
10 SSER
RTU fault exists: sets
TERMINAL FLAG bit.
47 SSBUSY
Subsystem cannot service
1553 request at this time.
48 ILLCMD
Mode command subsystem
illegalization: Sets MSGERR
bit, doesn’t suppress status
word.
Table 7 – Subsystem Control of RT-Status
1553 BUS ^{CMD RT}A ^{RCV P DATA (16 BITS) P}
NRGRNT (42)
BCSTRCV (75)
INCMD (9)
HANDSHAKE
(REQ, GRNT, ACK)
1.5µs
3.4±0.5µs
0.5µs
3.2±0.5µs
REF
10.75±0.75µs
7.5±0.5µs
3.9µs
STAT RT_A
5.5±0.5µs
P
7.5±0.5µs
4.5±0.5µs
SOM (78)
MEM-WRITE
(CS, WR, ADRINC)
D0 - D15
NODT (71)
STATEN (3)/
BUFFENA (58)
EOM (57)
WC_0-4 T/R (15)
CHA/CHB (16)
Aeroflex Circuit Technology
5.5±0.5µs
CMD
667ns
DATA
STAT
4µs
400ns
166ns
Note: All timing is typical unless otherwise noted.
Figure 16 – RT Receive Command Timing
16
SCDCT2565 REV B 8/10/99 Plainview NY [phone]