HD6433937 Datasheet, PDF (396/521 Pages) Hitachi Semiconductor – Hardware Manual

• The above operation is repeated for every temporary address.
12.5.5 Using the Receiver Shutdown Packet
The contents of this section apply to the FLEX™ Roaming Decoder. They are not applicable to
the FLEX™ Non-Roaming Decoder.
1. Calculating Time Left
The receiver shutdown packet gives timing information to the host. Two times are of particular
interest when implementing a roaming algorithm.
• TimeToWarmUpStart. Defined as the amount of time there is before the receiver will start to
warm up (i.e. transition from the off state to the first warm up state).
• TimeToTasksDisabled. Defined as the amount of time the host has to complete any host
initiated tasks (e.g. by setting SND or SAS in the roaming control packet).
The formula’s for calculating these times depend on whether the FLEX decoder is in synchronous
mode or asynchronous mode.
SYNCHRONOUS MODE:
TimeToWarmUpStart ≥ (TNF • 80ms) + (SkippedFrames • 1874.375ms) +
ReceiverOffTime –167.5ms
TimeToTasksDisabled ≥ (TNF • 80ms) + (SkippedFrames • 1874.375ms) – 247.5ms
ASYNCHRONOUS MODE:
TimeToWarmUpStart ≥ ((TNF –2) • 80ms) + ReceiverOffTime
TimeToTasksDisabled ≥ ((TNF –3) • 80 ms)
Where,
TNF:
SkippedFrames:
ReceiverOffTime:
Time to Next Frame. Value from the receiver shutdown packet.
The number of frames that won’t be decoded. This can be calculated
from the Current Frame (CF) and Next Needed Frame (NAF) fields in
the receiver shutdown packet (e.g. If CF is 10 and NAF is 12, then
SkippedFrames is 1)
The time programmed in the receiver off setting packet.
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