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Chapter 11: 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.
–
12V PC/104
-Plus
devices
The XE–900 does not provide
–
12V to the PC/104
-Plus
connector. If your PC/104
-
Plus
board requires
–
12V, you must power it from a source other than the PC/104
-
Plus
connector. If your power supply provides
–
12V, then you can power your
PC/104
-Plus
card from J8 pin 9. READ THE FOLLOWING CAUTION BEFORE
INSTALLING YOUR CARD.
CAUTION
On the XE–900 PC/104
-Plus
J3 connector, the
–
12V pin (A30) is tied to
ground (see table on page 110). If you do use a
–
12V PC/104
-Plus
card and
provide external power, you must clip pin A30 on your PC/104
-Plus
card
before you connect it to the XE–900. Otherwise, the
–
12V will be shorted to
ground and you will destroy your cards.
Содержание XE-900
Страница 19: ...19 Figure 2 1 XE 900 SBC component diagram top ...
Страница 20: ...20 Figure 2 2 XE 900 SBC component diagram bottom ...
Страница 21: ...21 Figure 2 3 XE 900 SBC dimensions without Integrated Conductive Cooling System ...
Страница 38: ...38 ...
Страница 91: ...91 Figure 15 2 Dimensions for the Integrated Conductive Cooling System ...