COMPONENT MAINTENANCE MANUAL
AVIATION RECORDERS
FA2100CVR
Rev. 15 Page 51
Apr. 14/16
Description and Operation
23–70–04
Use or disclosure of information on this sheet is subject
to the restrictions on the cover page of this document.
Each 32 Mb flash memory device in the CSMU contains 2 Mwords (16 bits per word)
of storage capacity. This 2 Mwords consists of 64 “Erase” Blocks which are each 32
Kwords long. An erase block is the smallest physical block of a flash memory device
that can be erased at one time.
The FA2100 CVR software partitions each 32 Mb Erase Block into an eight word header
followed by 910 logical packets of 36 words each. These packets are the fundamental
units which are built and stored into the CSMU. The header data includes partition,
channel, block number and other information that can be used to re-align and
re-assemble the physical memory devices should they become detached from the
printed wiring board during impact.
D.
Fault Processing
The Model FA2100 CVR software monitors virtually every internal data transaction
for anomalies. This includes all messaging between tasks, SMP to CSMU, and SMP
to GSE. The digitized audio data input stream from the Audio Compressor board is
also monitored for integrity.
The software also monitors itself for illegal or unexpected operations. Fault informa-
tion is stored in the NVRAM fault history log. The log can contain about 275 entries.
Of these, the first 255 entries are considered as “primary” events. If this portion of
the log fills, the remaining 20 “secondary” entries are used and overwritten as re-
quired. The log records the power up sequence number and the following informa-
tion for each event:
F
time (in seconds) from last power up
F
event class
F
task ID of event source
F
type of event
F
specific event code
F
event count (within this power up sequence)
The event class identifies the severity of the event detected. This allows the fault
log to be used for recording non
−
fault conditions that may help in determining sub-
sequent failure modes. The event classes reported by the software are:
F
EV
−
No fault, event recording only
F
NN
−
Fault, not latched, not fatal
F
LN
−
Fault, latched, not fatal
F
LF
−
Fault, latched fatal
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