5962F8957701VZC View Datasheet(PDF) - Aeroflex UTMC
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5962F8957701VZC Datasheet PDF : 61 Pages
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8.1 Monitor Functional Operation
The Bus Monitor function is a register-selectable mode of
operation. The host users registers 14, 16, and 17 in
conjunction with Register 0 to program the BCRTM to
monitor any combination of remote terminals or all of the
remote terminals.
the BCRTM’s memory mangement scheme gives the host a
great deal of flexibility for processing 1553 bus data and is
compatible with may bus monitoring applications. the host
CPU is responsible for processing initializing the Monitor
Control Blocks. The Monitor structure is analogous to the
Bus Controller Command Block scheme. the only real
difference is the direction of information flow.
The number of Monitor Control Blocks that the host
initializes depends on the data latency requirements for
post-processing of 1553 commands. the linked list of
Command Blocks could be connected in a loop fashion, with
the BCRTM accessing the loop at one point and the host
CPU processing the message behind that point. The bit
positions of the BM control/status word are defined as
shown in figure 20.
COMMAND BLOCK #1
CONTROL WORD
TP
#2
CONTROL WORD
TP
#3
CONTROL WORD
TP
#4
CONTROL WORD
TP
Figure 19. Monitor Command Block
Tail Pointers
15
CBA
7
TT7
B0 - B7
B8 - B11
B12 - Bus A/B:
B13 - IWA:
B14 - ME:
B15 - CBA:
14
13
12
11
10
9
8
ME
IOA
BA/B
X
X
X
X
6
5
4
3
2
1
0
TT6
TT5
TT4
TT3
TT2
TT1
TT0
Time Tag (64µs resolution)
Not Used
Defines which of the dual redundant 1553 buses on which the BCRTM received
this message
Interrupt When Addressed. The BCRTM issues a standard priority interrupt
when the monitor accesses this Bus Monitor Command block.
Message Error. The BCRTM sets this bit if a 1553 message error occurred while
receiving this message.
Command Block Activated. The BCRTM sets this bit when this Bus Monitor
Command Block is accessed by the BCRTM.
Figure 20: Bus Monitor Control/Status Word
8.2 Monitor Error Detection
in the Monitor mode, the BCRTM chaecks all monitored
messages for errors. Detectable errors include word count
errors, long words, short words, Manchester errors
(including zero crossing deviation), parity errors, and
data contiguity.
Due to the nature of the 1553 protocol, it ca be very difficult
for any monitoring device to interpret some types of errors
on the 1553 bus. For example, suppose an RT (whose RT
Address the BCRTM is monitoring) incorrectly responds to
a Broadcast command. The BCRTM, which is not receiving
or transmitting the message, cannot distinguish between the
erroneous status word and a new command sent from the
Bus Controller, since the status syncis identified to the
command sync. In this case, the BCRTM will put the extra
status word in a new Monitor Command Block, and then
report a Message Error due to the to the incorrect
protocol on the erroneously interpreted status word the
RT transmitted.
8.3 Monitor Operational Sequence
The following is a general description of the operation of
the BCRTM as it processes a monitored BC-to-RT message
in the Monitor mode. DMA operations will vary slightly
depending on the type of message (i.e., RT-to-BC, RT-toRT,
etc.) It is assumed that the user has already written a "1" to
BCRTM-35
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