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Programmable LED
Connector J14 includes an output signal for attaching a software controlled LED. Connect the
cathode of the LED to J14, 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
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. Refer to page 69 for further
information:
LED On
MOV
DX,1D0H
IN
AL,DX
OR
AL,80H
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.
External Speaker
A miniature 8 ohm speaker can be connected between J14, pin 50 (SPKO*) and J4, pin 49
(MKPWR). A speaker is provided on the CBR-5009 breakout board.
Push-Button Reset
Connector J14 includes an input for a push-button reset switch. Shorting J14, pin 37 to ground
causes the EBX-22 to reboot.
This connector uses IEC 61000-4-2-rated TVS components to help protect against ESD damage.
A reset button is provided on the CBR-5009 breakout board.
EBX-22 Reference Manual
LED Off
MOV
DX,1D0H
IN
AL,DX
AND
AL,7FH
OUT
DX,AL
Interfaces and Connectors
42
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