COMPONENT MAINTENANCE MANUAL
AVIATION RECORDERS
FA2100CVR
Rev. 15 Page 47
Apr. 14/16
Description and Operation
23–70–04
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(c)
The CVR Executive manages the storage of received channel specific au-
dio data packets to the CSMU. The CVR Executive examines the packet,
determines which memory partition should be addressed, and sends the
complete packet to the Flash Manager for storage in the CSMU. The CVR
Executive task also manages the erase look
−
ahead function to insure that
there is always a new erased block of flash memory available for impend-
ing memory write operations.
(d)
The Flash Manager stores the packet in the CSMU and performs a read
−
after
−
write for each word stored. The read
−
after
−
write data packet along
with error count is returned to the CVR Executive.
(e)
The CVR Executive checks for any CSMU access errors, logs error as ap-
propriate, and sends the 36 word read
−
after
−
write packet to the Audio Re-
constructer task.
(f)
The Audio Reconstructer task accumulates the channel specific audio
data packets and multiplexes them into the 2 ms. audio data frame format.
The reconstructed audio stream is transmitted via the TDM bus to the
GSE connector. If attached, this allows the GSE to monitor real time au-
dio that has been completely processed through the CSMU.
While in the record state, the Mode Executive monitors the delayed shutdown
input to the CVR. If asserted, and held, this will cause the Mode Executive to
start a shutdown timer. If the timeout occurs (within 10 minutes), Mode Execu-
tive will set a shutdown flag which is polled by the CVR Executive. This results
in a shutdown of record operation until the delayed shutdown input is de-as-
serted, or the timer is reset by an assertion of the “push
−
to
−
test” input.
(3)
Power Down State
Power down is initiated when the hardware detects an imminent power failure.
The hardware design is such that a power fail signal will be provided to the
SMP at least 50 milliseconds before reset will occur. This input to the SMP is
detected by the CVR executive task. This task then proceeds to effect an or-
derly shutdown of record operations within the CVR. The shutdown sequence
is as follows:
(a)
After sensing the power fail input, the CVR executive sends a “stop re-
cording” message to the Audio Channelizer task. The Audio Compressor
hardware is disabled to stop the flow of audio data into the SMP. The
CVR executive then starts a timer while waiting for the Audio Channelizer
task to respond to the shutdown message. During this time, all processed
audio data will continue to be received from the Audio Channelizer and
sent to crash protected flash memory as in normal record mode. The Au-
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