Chapter 12: PC/104 expansion
Description
The PC/104 connector allows you to interface expansion modules such as A/D
converters, CardBus, digital I/O, serial ports, etc. Modules can be stacked to form a
highly integrated control system.
Note
The actual maximum number of modules in a stack is limited primarily to the
capacitive loading on the bus and the electrical noise environment. This is
especially true when wide temperature operation is required. Good design practice
dictates that the modules present only one load to each bus signal. Unfortunately,
there are modules on the market that violate this practice by loading the bus more
heavily. Typically, it is the IOW*, IOR*, MEMW*, and RSTDRV* lines. For
example, if the IOW* line is routed to four ICs on the module without a buffer, then
the loading is equivalent to four PC/104 modules. Stacks with three or more
expansion modules should be carefully tested under all environmental conditions.
If possible, query the manufacture of the expansion module regarding loading. All
Octagon products present one load.
Figure 12–1 Typical PC/104 module stack
PC/104 Connectors
XE–700
Standoff
PC/104 expansion
Standoff
WARNING!
When installing any PC/104 module, avoid excessively flexing the
XE–700 SBC. Mate pins correctly and use the required mounting
hardware.
Note
See
Appendix A - Connectors
for mating information.
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