CT2565 Aeroflex Circuit Technology, CT2565 Datasheet - Page 19

• Manufacturer Part Number: CT2565
• Description: CT2565 Bus Controller/ Remote Terminal and BUS Monitor FOR MIL-STD-1553B
• Manufacturer: Aeroflex Circuit Technology

Aeroflex Circuit Technology
In the MT mode, the CT2565 captures all valid
transmissions on both channels of the 1553 bus, allowing
the user to monitor bus activity. Each word is transferred to
the subsystem along with an identification for interpretation
of the 1553 data stream.
Initialize the CT2565 for MT operation per Table 2. The
CT2565 will remain in an idle state until BCSTART (pin 41)
is pulsed low. Figure 21 illustrates MT operation.
Valid words received by the CT2565 are transferred to the
subsystem along with an identification Word by a single
DMA handshake with two memory-write operations shown
in Figure 22, MT Transfer Timing. Since the decoder will
reject words based on sync field errors and/or errors in the
first 2 non-sync bits, these words will not be processed
further (i.e., the subsystem will receive no indication of the
receipt of this word).
Note: Subsystem should clear entire memory prior to start of MT
MT Operation
MT Initialization
NAME
GAP TIME
WORD TRANSFER
WORD TRANSFERRED
VALID WORD
COMMAND SYNC
CHAN A/B
WORD GAP
WORD TRANSFER
LOGIC "1"
LOGIC "1"
VALID WORD
COMMAND SYNC
CH A/B
WORD GAP
SET TO "0"
operation.
Figure 20 – Identification Word
15
GAP TIME
NODT low time. 2MHz Clock
allows 500ns increments to
128µs (remains static at FF on
overflow).
Logic "1" indicates successful
transfer to subsystem.
Indicates successful transfer
(See bit 7)
Reset (1) indicates Manchester
error, Parity error, Low Bit Count
and/or Status sync field.
Logic "1" indicates Command or
Status sync field. Logic "0"
indicates data sync.
Logic "1" if word received on
1553 bus Channel B.
Set (0) if current word was
received at least 2µs after
receipt of previous word (parity
to mid-sync).
8 7
Definition
0
19
Figure 21 – MT Operation Flow Chart
Notes:
(1) Steps marked with " _ _ _" indicates operation is
(2) Steps marked with " ___" indicates user interaction
transparent to user.
required.
SCDCT2565 REV B 8/10/99 Plainview NY [phone]
INCREMENT MEM ADDR
INCREMENT MEM ADDR
IDENTIFICATION WORD
START MT OPERATION
DECODER CHECK
(START-UP ONLY)
MEMORY WRITE
MEMORY WRITE
INITIALIZATION
SYNC + 2 BITS
1553 INPUT
NODT LOW
1553 BUS
ACTIVITY
ERROR
START
DMA
YES
?
NO
YES