HD-6408 查看數據表（PDF） - Renesas Electronics
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HD-6408 Datasheet PDF : 12 Pages
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HD-6408
Decoder Operation
The Decoder requires a single clock with a frequency of 12
times the desired data rate applied at the DClock input. The
Manchester II coded data can be presented to the Decoder in
one of two ways. The BOI and BZI inputs will accept data from
a differential output comparator. The UDI input can only accept
noninverted Manchester II coded data (e.g. from BOO of an
Encoder through an inverter to UDI).
The Decoder is free running and continuously monitors its data
input lines for a valid sync character and two valid Manchester
data bits to start an output cycle. When a valid sync is
recognized (1), the type of sync is indicated by the CDS output.
If the sync character was a command, this output will go high
(2) and remain high for sixteen DSC periods (3), otherwise it
will remain low. The TD output will go high and remain high (2)
- (3) while the Decoder is transmitting the decoded data
through SDO.
The decoded data available at SDO is in a NRZ format. The
DSC is provided so that the decoded bits can be shifted into an
external register on every low-to-high transition of this clock (2)
- (3). Note that DECODER SHIFT CLOCK may adjust its
phase up until the time that TAKE DATA goes high.
After all sixteen decoded bits have been transmitted (3) the
data is checked for odd parity. A high on VW output (4)
indicates a successful reception of a word without any
Manchester or parity errors. At this time the Decoder is looking
for a new sync character to start another output sequence.
VALID WORD will go low approximately 20 DECODER SHIFT
CLOCK periods after it goes high if not reset low sooner by a
valid sync and two valid Manchester bits as shown (1).
At any time in the above sequence a high input on DR during a
low-to-high transition of DSC will abort transmission and
initialize the Decoder to start looking for a new sync character.
TIMING
DSC
BOI
BZI
TD
CDS
SDO
VW
0
1
2
3
4
5
6
7
8
1ST HALF 2ND HALF 15 14 13 12 11 10
SYNC SYNC 15 14 13 12 11 10
UNDEFINED
FROM PREVIOUS RECEPTION
15 14 13 12
12
16 17 18 19
2
1
2
1
0
P
0
P
4
3
2
1
0
34
FN2952 Rev 3.00
October 1, 2015
Page 5 of 12
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