Interfaces and Connectors
VL-EPICs-36 Reference Manual
40
Programmable and Power LEDs
Connector J13 includes an output signal for attaching a software controlled LED. Connect the
cathode of the LED to J13 pin 48; 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 1D0h (or 1E0h). 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.
LED On
LED Off
MOV
DX,1D0H
MOV
DX,1D0H
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.
Internal Speaker
A miniature 8 ohm speaker can be connected between J13 pin 50 (Speaker Drive) and pin 49
(+5.0V). A speaker is provided on the VL-CBR-5009 breakout board.
