HD6433937 Datasheet, PDF (388/521 Pages) Hitachi Semiconductor – Hardware Manual

4. Receiver Shut Down Sequence
The FLEX decoder allows for up to 3 steps associated with shutting down the receiver. When the
FLEX decoder decides to turn off the receiver, the first shut down setting, if enabled, is applied to
the receiver control lines for the corresponding shut down time. At the end of the last used shut
down time, the “Off” setting is applied to the receiver control lines. If the first shut down setting is
not enabled, the FLEX decoder will transition directly from the current on setting to the “Off”
setting. The receiver turn off sequence when all shut down settings are enabled is shown in figure
12-11.
If the receiver is on or being warmed up when the decoder is turned off (by clearing the ON bit in
the Control Packet), the FLEX decoder will execute the receiver shutdown sequence. If the FLEX
decoder is executing the shut down sequence when the FLEX decoder is turned on (by setting the
ON bit in the Control Packet), the FLEX decoder will complete the shut down sequence before
starting the warm up sequence.
Shut Down
Time 1
Shut Down
Time 2
RECEIVER
CONTROL
1600sps or 3200sps
Sync or Data Setting
Shut Down
Setting 1
Shut Down
Setting 2
Off
LINE SETTING
Possible
LOBAT
Check
Possible
LOBAT
Check
Possible
LOBAT
Check
Figure 12-11 Receiver Shut Down Sequence
5. Miscellaneous Receiver States
In addition to the warm up and shut down states, the FLEX decoder has four other receiver states.
When these settings are applied to the receiver control lines, the FLEX decoder will be decoding
the EXTS1 and EXTS0 input signals (or the equivalent internal signals when using the internal
demodulator/data slicer). The timing of these signals and their duration depends on the data the
FLEX decoder decodes. The four settings are as follows:
• 1600sps Sync Setting:This setting is applied when the FLEX decoder is searching for a 1600
symbols per second signal.
• 3200sps Sync Setting:This setting is applied when the FLEX decoder is searching for a 3200
symbols per second signal.
• 1600sps Data Setting:This setting is applied after the FLEX decoder has found the C or C
sync word in a 1600 symbols per second frame.
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