Specifications

Little Board/P5i Technical Manual
2–4
2.1.2 Connectors
The I/O connectors are shrouded dual-row male headers for use with flat ribbon (IDC) female connectors
and ribbon cable. Ampro recommends that you use “center-bump polarized” connectors to prevent
accidentally installing cables backwards. Use non-strain-relief connectors to stay within the vertical
height envelope shown in Figure 1–1.
Many of the connectors have “key pins”. Install a blocking key in the corresponding connector socket on
the mating ribbon cable to prevent misalignment.
If you use the recommended mating connectors, you can install retaining clips to secure a cable to its
connector. (The connector heights of some brands do not allow the use of retaining clips.) Retaining
clips are especially useful in high-vibration environments.
You can also design a PC board assembly, made with female connectors in the same relative positions as
the Little Board’s connectors, to eliminate cables, meet packaging requirements, add EMI filtering, or
customize your installation in other ways. Precise dimensions for locating connectors are provided in
Figure 1–1.
The ISA portion of the PC/104-Plus expansion bus appears on two connectors (P1 and P2). You can
expand the system with on-board MiniModule products or other PC/104-compliant expansion modules.
These modules stack directly on the connectors, or use conventional or custom expansion hardware,
including solutions available from Ampro.
The PCI portion of the PC/104-Plus expansion bus appears on connector J21. It uses a 2 mm. 4-row
connector called out in the PC/104-Plus draft specification. Like the P1/P2 connectors, J21 has both male
and female connections, allowing for “stackthrough” assembly.
If you plan to use the on-board video controller with a flat-panel LCD screen requiring a Vee bias
voltage supply, you can install Ampro’s optional LCD Bias Supply board on connector J4, as shown in
Figure 2-1. This board can be jumpered to supply positive or negative Vee from ±15V to ±35V
(adjustable). (Only certain LCD panels require an external Vee supply.)
2.1.3 Jumper Configuration Options
Ampro installs option jumpers in default positions so that in most cases the Little Board/P5i requires no
special jumpering for standard AT operation. You can connect the power and peripherals and operate it
immediately. The only jumpers of concern are those that configure the byte-wide socket for a device you
install.
Jumper-pin arrays are designated W1, W2, and so forth. Jumper pins are spaced 2 mm apart. A square
solder pad identifies pin 1 of each jumper array. Table 2-2 is a summary of jumper use. In the Default
column, two numbers separated by a slash (for example, 1/2) means that pins 1 and 2 are shorted with a 2
mm jumper block.