Xycom XVME-400, Руководство пользователя

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XVME-400/40 l/490/491 Manual
October, 1989
2.4.4 +5V Power Supply (Jl, J2; XVME-401 only)
On the XVME-401, jumpers Jl and J2 control whether the +5V supply is brought out to
front-edge connectors JKl and JK2. Table 2-6 indicates the functions of these jumpers.
Table 2-6. +5V Jumpers (XVME-401 only)
Jumper Use
I
J l
If Jl is installed, +5V will be connected to JKl (pin 47).
If Jl is removed, JKI-47 will float.
J 2 If J2 is installed, +5V will be connected to JK2 (pin 47).
If J2 is removed, JK2-47 will float.
The +5V signals on the front-edge connector could be used to provide external line
termination by being used as a pull-up voltage, or for biasing.
2.4.5 Tri-stating the Serial Channels (J3-J6; XVMIE-401/491 only)
T
O
facilitate multidrop configurations, all drivers associated with a particular
communication channel may be tri-stated or enabled via SCC output pin RTS*. Each
channel has its own jumper to determine how the RTS* output affects line driver
enabling.
When a channel’s jumper is in the A position, the line drivers associated with that channel
for TT, RS, SD, and TR will be controlled by RTS *. When RTS* is negated (high voltage),
all line drivers associated with that channel will be tri-state. When RTS* is asserted, all
line drivers associated with that channel will be enabled. When a channel’s jumper is in
the B position, the line drivers associated with that channel will be enabled, regardless of
the state of the SCC output RTS*.
The jumper numbers related to the serial channel numbers are shown below and are all
shipped in the B position:
J3 Channel 3
J4 Channel 2
J 5 Channel 1
J6 Channel 0
2.4.6 Daisy Chain Signals
Each slot in the VME backplane must propagate the Daisy Chain signals to the next
backplane slot.
This occurs automatically if boards are installed in the slots. Where
boards are not installed, the appropriate backplane jumpers must be installed to continue
the signal path.
NOTE
Boards and jumpers should never both be installed in any one slot.
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