Interfaces and Connectors
EBX-37 Reference Manual
43
PS/2 Keyboard and Mouse (J18)
A standard PS/2 keyboard and mouse interface is accessible through connector J4 of the
VersaLogic VL-CBR-5009 breakout board. The breakout board is connected to connector J18 of
the VL-EBX-37. The +5V power provided to the keyboard and mouse is protected by a 1 Amp
fuse.
This connector uses IEC 61000-4-2-rated TVS components to help protect against ESD damage.
Table 16: PS/2 Mouse and Keyboard Pinout
VL-CBR-5009
J4 Top Pin
Signal
Description
1
MSDATA
Mouse Data
2
–
No Connection
3
GND
Ground
4
MKPWR
+5V (Protected)
5
MSCLK
Mouse Clock
6
–
No Connection
VL-CBR-5009
J4 Bottom Pin
Signal
Description
1
KBDATA
Keyboard Data
2
–
No Connection
3
GND
Ground
4
MKPWR
+5V (Protected)
5
KBCLK
Keyboard Clock
6
–
No Connection
Programmable LED (J18)
Connector J18 includes an output signal for attaching a software controlled LED. Connect the
cathode of the LED to J18, pin 48, and connect the anode to +5V. An on-board resistor limits the
current to 15 mA when the circuit is turned on. A programmable LED is provided on the VL-
CBR-5009 breakout board.
To turn the LED on and off, set or clear bit D7 in I/O port CA0h (or C90h). When changing the
register, make sure not to alter the values of the other bits.
The following code examples show how to turn the LED on and off. Refer to page 54 for further
information:
LED On
LED Off
MOV
DX,CA0H
MOV
DX,CA0H
IN
AL,DX
IN
AL,DX
OR
AL,80H
AND
AL,7FH
OUT
DX,AL
OUT
DX,AL
Note
The LED is turned on by the BIOS during system startup. This causes the light to
function as a "power on" indicator if it is not otherwise controlled by user code.
