Specifications

EPC-8A Hardware Reference
8
The daisy-chain signal concept is shown in Figure 2-2. The Slot-1 controller board
initiates each daisy-chain signal. Each VMEbus slot to the right of the Slot-1 controller
must pass through each of the daisy-chain signals. For each VMEbus slot, xxxIn pin must
be connected to its corresponding xxxOut pin (For example, BG0In to BG0Out, BG1In to
BG1Out,...,IackIn to IackOut) either through the board in that slot or by jumpers. (Boards
that meet VMEbus specifications correctly handle the signals and do not need backplane
jumpers. However, many early designs may not propagate these signals correctly.) may
not handle any of these signals. Check the manual for each board to be installed to
determine if these signals are passed through correctly. If they are not, or if the VMEbus
slot is empty, all (or some) of these signals must be jumpered. See Figures 2-3 and 2-4 on
the following pages for examples.
The figure above shows the jumpers required for a five-slot EPC-8A subsystem,
consisting of a two-slot EPC-8A, an EXP-MC module carrier for two additional EXM
modules, and an EXP-MX storage module. Note that the left-most slot does not require
any jumpers. All other slots occupied by the subsystem require all five jumpers be
installed.
Once you determine where the jumpers need to be, you must determine how to jumper
your particular backplane. Different backplane manufacturers handle this in different
ways; some provide stake pins on the rear of the backplane while others provide stake pins
on the front of the backplane. These stake pins can be located in several different places.
Figure 2-3. Backplane Jumpers Required for EPC-8A Subsystem
indicates jumper needed
BG0
BG1
BG2
BG3
IACK
EPC-8A EXP-MC
(optional)
EXP-MX
Mass Storage Module