ARM Technical Support Knowledge Articles

PORT2 LEDS DO NOT WORK

Applies to: EPM900 LPC Emulator

Answer


Information in this article applies to:


QUESTION

I am using the EPM900 and I have written a program that outputs bit-patterns on port 2. I expected the LED's on the board to blink, but they did not. What is wrong?

ANSWER

Basically there are two reasons for this problem.

  1. P2 LED Driver is disabled: You must select Enable P2 LED Driver under Project -> Options for Target -> Debug -> EPM900 Settings. This option enables the P2.0-P2.7 LEDs (that are driven by a buffer) and show Port 2 status information.

    The LED driver is disabled by default to avoid oscillation on open device inputs. You should disable this option when you are using the P2 pins as input without proper pull-up resistors.

  2. KeilLP.SYS driver is not up-to-date: This file is installed in Windows/System32/Drivers or WinNT/System32/Drivers (for Windows 2000). The current KeilLP.SYS file is Version 1.12 dated 2. Feb. 2003. When you have an older version, you should download the KeilLP.SYS driver from the Attached Files section below, and extract the files to the appropriate Windows drivers folder described above. You need to reboot your computer after changing the KeilLP.SYS driver file. The driver update does not work if the EPM900 Emulator/Programmer is already connected. You must re-start your computer with the EPM900 disconnected before you can update this file.

MORE INFORMATION

Article last edited on: 2005-07-22 16:43:56

Rate this article

[Bad]
|
|
[Good]
Disagree? Move your mouse over the bar and click

Did you find this article helpful? Yes No

How can we improve this article?

Link to this article
Copyright © 2011 ARM Limited. All rights reserved. External (Open), Non-Confidential