HD3-15531B-9 INTERSIL [Intersil Corporation], HD3-15531B-9 Datasheet - Page 9

• Manufacturer Part Number: HD3-15531B-9
• Description: CMOS Manchester Encoder-Decoder
• Manufacturer: INTERSIL [Intersil Corporation]

MIL-STD-1553
The 1553 Standard defines a time division multiplexed data
bus for application within aircraft. The bus is defined to be
bipolar, and encoded in a Manchester II format, so no DC
component appears on the bus. This allows transformer cou-
pling and excellent isolation among systems and their envi-
ronment.
The HD-15531 supports the full bipolar configuration,
assuming a bus driver configuration similar to that in
Figure 1. Bipolar inputs from the bus, like Figure 2, are also
accommodated.
The signaling format in MIL-STD-1553 is specified on the
assumption that the network of 32 or fewer terminals are
controlled by a central control unit by means of Command-
“0”
“1”
BIPOLAR ZERO IN
COMMAND SYNC
BIPOLAR ONE IN
PARALLEL OUT
VALID WORD
FIGURE 6. SIMPLIFIED MIL-STD-1553 DRIVER
FROM PREVIOUS
RECEPTION
VALID
SYNC
MSB
FIGURE 5. DECODER TIMING
BUS
HD-15531
9
Words, and Data. Terminals respond with Status Words, and
Data. Each word is preceded by a synchronizing pulse, and
followed by parity bit, occupying a total of 20µs. The word
formats are shown in Figure 4. The special abbreviations are
as follows:
P
R/T
ME
TF
LSB
FIGURE 7. SIMPLIFIED MIL-STD-1553 RECEIVER
Parity, which is defined to be odd, taken across all
17 bits.
Receive on logical zero, transmit on ONE.
Message Error if logical 1.
Terminal Flag, if set, calls for controller to request
self-test data.
PARITY
P
P
VALID
+
-
-
+
“1” REF
“0” REF
“1”
“0”