COMPONENT MAINTENANCE MANUAL
AVIATION RECORDERS
FA2100CVR
Rev. 15 Page 49
Apr. 14/16
Description and Operation
23–70–04
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(5)
Bulk Erase State
The bulk erase operation is initiated by assertion of the bulk erase discrete in-
put to the recorder. After this input has been detected by the Mode Executive
task for at least two seconds (usually by depressing a push button on the con-
trol unit in the cockpit), the bulk erase command is sent to the CVR Executive.
The CVR Executive task will cycle through each erase block in the CSMU and
set the bulked erased flag which is part of the eight word block header. The
CVR Executive will prevent the playback of any CSMU memory block which
has been marked as bulk erased. The bulk erase flag in each block is reset
during normal record state operation. During the bulk erase operation the CVR
Executive controls a 400 Hz tone which is inserted on the monitor audio chan-
nel to confirm bulk erase state operation.
(6)
Push to Test State
The built in test capability includes the push to test state which is initiated and
controlled by the push to test discrete input to the CVR. Assertion of the push
to test input (usually by depressing a push button on the control unit in the
cockpit) is detected by the Mode Executive task.
Once this input is detected, the Mode Executive will start the test sequence
which takes about two seconds to complete. A 640 Hz analog tone of about
200 ms duration is inserted sequentially into each of the audio input channels
and recorded. The tone is detected on the Audio Compressor board in the
monitored audio channel. Proper detection is checked by the Mode Executive
and, if detected correctly on all inputs, and no other fault condition exists, a
“good” or “passed” indication is asserted and held for about one second. Such
an indication is usually displayed on the control panel in the cockpit.
C.
Data Structures
The primary data structure utilized in the FA2100 CVR is the organization of the
crash protected flash memory contained in the CSMU. The partitioning of the
2-Mwords chips (32 Mb) of the CSMU memory provides for the physical separation
of the individual audio partitions needed for the storage of the HQV, HQC, SQV, and
SQC channels (per ED
−
56A).
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