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Signal
Connections
OPTION-
01T/Passport
PCB Sub-
assembly
Backplane/
Mezzanine PCB
Subassembly
1260-100X Theory of Operation B-2
Connectors P1, P2, P3, and P4 connect to the VXIbus backplane.
Connectors J8 and J9 pass the VXI bus signals and +5V, +12V
and +24V to the Option-01T/Passport PCB subassembly.
DIP switches S1 pins 1 through 6 and S2 pins 1 through 6 set the
local bus pass through. S2 pin 7 sets the module address of the
plug-ins. If S2 pin 7 is set to OFF position, the module addresses
of the plug-ins are set to operation from 1 through 6. If S2 pin 7 is
set to ON position, the module addresses of the plug-ins are set to
operate from 7 through 12. which connects to the VXI backplane.
The Bridge then connects to these signals using its P2 connector.
Currently Option-01T controller circuit is not available for 1260-
100X carrier. So the 1260-100X is controlled by another carrier
with Option-01T installed.
Without the Option-01T controller circuit, the Option-01T/Passport
PCB subassembly only provides the pass through local bus
signals, +5V, +12, +24V power and Ground signals to the
Backplane/Mezzanine PCB subassembly.
Signals
The backplane/Mezzanine PCB subassembly provides bridging
functions between the plug-ins and the Option-01T/Passport PCB
subassembly.
All communications signals are connected in
parallel to all six plug-ins, except LBOARDSEL1 through
LBOARDSEL6. These six signals route to their respective plug-in
slots, and identify which plug-in is currently addressed.
The backplane also provides an analog bus. This bus consists of
four pairs of PCB traces that daisy-chain from one plug-in to the
next, connecting to all six slots in parallel. Each pair of traces is
impedance-matched to 50 ohms, and is routed for maximum
isolation and minimum crosstalk.
1260-100X User Manual
Racal Instruments © 2005
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