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METER
CONNECTOR
(J1202)
Figure
2.
Diagnostic Metering Panel - Edge View
FAEPS-36238-A
(1624)
3.
Diagnostic
Metermg
Panel - Internal View
data lines define 16 words of 4~bits each, or 64 total bits
as shown in Table 1. These bits form a multi-directional
digital communications path. The bus is multiplexed to
conserve interconnections (64 connections reduced to 9)
and to increase future expansion capability. The data
strobe and the four address lines are driven by the
control module. The data lines are.inverted and open col-
lector driven in both the station control module and the
DMP. This allows the station control module and the
DMP to drive the same bit in a nondestructive, wired
"OR" fashion.
The MUXbus timing diagram is shown in Figure 4. The
address lines are incremented once, approximately every
310 microseconds. The address changes when data strobe
is inactive CDS = 1). The data must be valid for 1 micro-
7/15/90
edge of DS. The data must be val-
the rising edge of DS. At cer-
the MUXbus may be momentarily halted (e.g.,
halt is, in effect, an extended
strobe. The address lines will be
",AllH,d\!,
Uti, WIn
remam at the address of the MUXbus
to the halt. The data lines are in a "don't
a halt and may be random.
any module other than the
control
does not change the state
of the station is called a "status only" bit. As an example
of a "status
Transmitter Activity (IX ACT) is
activated
station control module whenever the
transmitter
keyed. But, if the DMP
activates TX
the transmitter will not key. Thus, TX
68P81114E03
3
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