20
CMA22M cpuModule
BDM-610000069
Rev A
Connecting to the Stack
The bus connectors of the cpuModule are simply plugged onto a PC/104 stack to connect to other devices.
Follow the procedure below to ensure that stacking of the modules does not damage connectors or electronics.
For mechanical dimensions, including board-to-board spacing, see
1.
Turn off power to the PC/104 system or stack.
2.
Always work at an ESD protected workstation, and wear a grounded wrist-strap.
3.
Select and install stand-offs to properly position the cpuModule on the stack.
4.
Remove the cpuModule from its anti-static bag.
5.
Check that pins of the bus connector are properly positioned.
6.
Check the stacking order; make sure all of the busses used by the peripheral cards are connected to the
cpuModule.
7.
Hold the cpuModule by its edges and orient it so the bus connector pins line up with the matching
connector on the stack.
8.
Gently and evenly press the cpuModule onto the PC/104 stack.
Connecting to the PC/104-
Plus
(PCI) Bus
There are two additional considerations to make when using the PCI bus:
•
Slot selection switches on add-in boards
•
PCI bus signaling levels
Slot Selection Switches
Unlike PCIe cards, PC/104-
Plus
and PCI-104 expansion cards have a “slot” selection switch or jumpers. In total,
there are 4 PCI cards that can be stacked onto the cpuModule with switch positions 0 through 3. The distance
from the CPU determines these switch settings. The card closest to the CPU is said to be in slot 0, the next closest
slot 1 and so on to the final card as slot 3.
The “slot” setting method may vary from manufacturer to manufacturer, but the concept is the same. The CPU
is designed to provide the correct delay to the clock signals to compensate for the bus length. The correct switch
setting ensures the proper clock delay setting, interrupt assignment, and bus grant/request channel assignment.
Refer to the expansion board’s manual for the proper settings. Each expansion card must be in a different slot.
PCI Bus Signaling Levels
The PCI bus can operate at +3.3 V or +5 V signaling levels. The default PCI bus signaling level is +3.3 V. For more
information, contact RTD Technical Support.
WARNING
Do not force the module onto the stack! Wiggling the module or applying too much pressure
may damage it. If the module does not readily press into place, remove it, check for bent pins or
out-of-place keying pins, and try again.
WARNING
You will have to ensure that all your expansion cards can operate together at a single
signaling level.
Summary of Contents for cpuModule CMA22M Series
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