CT2554 Aeroflex Circuit Technology, CT2554 Datasheet - Page 18

• Manufacturer Part Number: CT2554
• Description: Ct2553 / 2554 / 2555 / 2556 Advanced Integrated Mux Aim Hybrid For Mil-std-1553
• Manufacturer: Aeroflex Circuit Technology

Aeroflex Circuit Technology
SA/MC0-4, T/R
ADDITIONAL FEATURES. Four 1553 Status
Word flags can be programmed via the
appropriate
addition, setting Interrupt Mask Register bits will
result in a low pulse on the Interrupt (INT) pin
with each occurrence of the respective error or
end of message condition. (See Configuration
Register and Interrupt Register sections.)
THIS RT: Each command appearing on either
1553
Manchester/protocol
receives a valid command word containing a
RTU address equivalent to the RTAD0-RTAD4
inputs (pins 10, 9, 50, 49, and 11, respectively),
THIS-RT (pin 55) will be pulsed low. This signal
can be used to identify specific 1553 commands.
This signal is also active in the BC mode.
Command Illegalization (Optional). The CT2553
has the capability to illegalize MIL-STD-1553
mode commands. In addition, valid non-mode
commands can be illegalized based upon the
Command Word subaddress field. An illegal
command is identified by driving the Illegal
Command, ILLCMD (pin 12) input low. The
CT2553 multiplexes the Word Count and
Subaddress fields (pins SA/MC0 - SA/MC4).
The CT2553 responds to illegalized commands
by transmitting its Status Word with the Message
ILLCMD
LMC
SYMBOL
Bus
t1
Configuration
is
Figure 23 – Mode Command/Sub-Address Illegalization Timing
decoded
errors.
DESCRIPTION
LMC to ILLCMD latch
Register
and
If
Mode Command Illegalization Timing
the
tested
bits.
CT2553
t1
for
In
LATCHED UNTIL NEXT VALID COMMAND WORD RECEIVED
VALID UNTIL NEXT VALID COMMAND WORD RECEIVED
18
Error bit set. No data words are transmitted;
received words, however, are placed in the
shared RAM locations indicated by the current
area Look-Up Table.
Upon receipt of a valid mode command, the
CT2553 will output the Command Word-Word
Count field and set the Latched Mode Command
(LMC) output to a logic 1. Upon receipt of a valid
non-mode command, the CT2553 will output the
Command Word-Subaddress field and set the
Latched Mode Command (LMC) output to a
logic 0.
An external PROM can be used for command
illegalization
count/subaddress, LMC and Broadcast Received
(BCSTRCV) bits and driving ILLCMD low where
appropriate (See Figure 23).
BUSY BIT. If the user asserts the BUSY bit low
in the Configuration Register, the CT2553 will
respond with a Status Word with the BUSY bit
set. In addition, no data words will be transferred
from the shared RAM as indicated by the
corresponding value in the current area Look-Up
Table. The CT2553 will transfer data associated
with a Receive Command into memory but will
not transmit data out onto the MIL-STD-1553 bus
when busy upon receipt of a Transmit Command.
MIN
by
250
SCDCT2553 REV B 8/6/99 Plainview NY [phone]
decoding
MAX
-
the
UNITS
ns
word