Ampro Corporation LITTLE BOARD P5X - Manual (Page 70)

2–52
Table 2– 39. J16 Mating Connector
Connector Type Mating Connector
RIBBON 3M 3452-7600
Latching Clip 3505-8016
DISCRETE WIRE MOLEX Housing 22-55-2162
Pin 16-02-0103
LED Connection
To connect an external LED power-on indication lamp, connect the LED anode to J16-5 and the
cathode to ground. J16-5 provides +5V through a 300 ohm resistor.
Speaker Connections
The board supplies about 100 mW for a speaker on J16-7. Connect the other side of the speaker to
ground (J16-8). A transistor amplifier buffers the speaker signal. Use a small general purpose 2 or 3
inch permanent magnet speaker with an 8 ohm voice coil. Refer to Chapter 3, Section 3.14 for an
explanation of the PC speaker circuit architecture.
Push-button Reset Connection
J16-9 provides a connection for an external normally-open momentary switch to manually reset the
system. Connect the other side of the switch to ground. The reset signal is “de-bounced” on the
board.
Keyboard Connection
You can connect an AT (not PC) keyboard to the keyboard port. J16-11 through J16-14 provide this
function. Normally, AT keyboards include a cable that terminates in a male 5-pin DIN plug for
connection to an AT (or a 6-pin miniature DIN plug for PS-2). Table 2– 47 gives the keyboard
connector pinout and signal definitions, and includes corresponding pin numbers for DIN keyboard
connectors.
Table 2– 47 Keyboard Connector (J16)
J16 Pin Signal Name DIN-5
Pins
DIN-6
Pins
12 Keyboard Clock 1 5
11 Keyboard Data 2 1
13 Ground 4 3
14 Keyboard power 5 4