Chapter 12: PC/104 and PC/104 Plus expansion
Description
The PC/104 and PC/104
Plus
connectors allow 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. The PC/104
Plus
expansion bus
supports mastering devices.
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.
The situation is even more critical for the PC/104
Plus
connector since the bus
speed is four times faster. The PC/104
Plus
connector and the PC/104
Plus
module
represent one load each. Adding more than one PC/104
Plus
module (two loads)
should trigger the same testing as discussed in the previous paragraph.
Figure 12–1 Typical PC/104 module stack
PC/104 Connectors
XE–800
Standoff
PC/104 or PC/104
Plus
expansion
Standoff
PC/104
Plus
WARNING!
When installing any PC/104 or PC/104
Plus
module, avoid excessively
flexing the XE–800 SBC. Mate pins correctly and use the required
mounting hardware.
Note
See
Appendix A - Connectors
for mating information.
75
Содержание XE-800
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Страница 19: ...Figure 2 2 XE 800 SBC component diagram bottom 19 ...
Страница 20: ...Figure 2 3 XE 800 SBC dimensions 20 ...
Страница 89: ...MOV AX 0fb0bh MOV DX 0ffffh INT 17h MOV aData AL if aData 1 printf U1 jumper is ON n 89 ...