Ampro Corporation LITTLE BOARD P5X - Manual (Page 72)

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PC/104-Plus EXPANSION BUS
The PC/104-Plus expansion bus appears on three header connectors, P1, P2, and J21. P1 is a 64-pin
female dual-row header. P2 is a 40-pin female dual-row header, and J21 is a 120-pin 2mm female
quad-row header (4 x 30). The PC-bus subset of the PC/104-Plus expansion bus connects to P1. The
AT expansion bus signals connect to P2. The layout of signals on P1 and P2 is compliant with the
PC/104 bus specification, and make up the ISA bus portion of the PC/104-Plus bus. An
implementation of the PCI bus appears on J21.
PC/104-compatible expansion modules can be installed on the Little Board/P5x expansion bus. The
buffered output signals to the expansion bus are standard TTL level signals. All inputs to the Little
Board/P5x operate at TTL levels and present a typical CMOS load to the expansion bus.
On-board MiniModule Expansion
You can install one or more Ampro MiniModule products or other PC/104 modules on the Little
Board/P5x expansion connectors. When installed on P1 and P2, the expansion modules fit within
the Little Board/P5x’s outline dimensions. Most Ampro MiniModule products have stackthrough
connectors compatible with the PC/104 specification. You can stack several modules on the Little
Board/P5x headers. Each additional module increases the thickness of the package by 0.66 inches
(15 mm). See Figure 2– 5.
Figure 2– 5. Stacking PC/104 Modules on the Little Board/P5x