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Intel® Server Boards S5000PSL and S5000XSL TPSAppendix C: POST Code Diagnostic LED Decoder
Appendix C: POST Code Diagnostic LED Decoder
During the system boot process, the BIOS executes a number of platform configuration
processes, each of which is assigned a specific hex POST code number. As each configuration
routine is started, the BIOS displays the POST code to the POST Code Diagnostic LEDs on the
back edge of the server board. To assist in troubleshooting a system hang during the POST
process, the Diagnostic LEDs can be used to identify the last POST process that was executed.
Each POST code is represented by a combination of colors from the four LEDs. The LEDs are
capable of displaying three colors: green, red, and amber. The POST codes are divided into two
nibbles, an upper nibble and a lower nibble. Each bit in the upper nibble is represented by a red
LED and each bit in the lower nibble is represented by a green LED. If both bits are set in the
upper and lower nibbles then both red and green LEDs are lit, resulting in an amber color. If
both bits are clear, then the LED is off.
A. Status LED D. Bit 2 LED (POST LED)
B. ID LED E. Bit 1 LED (POST LED)
C. MSB LED (POST LED) F. LSB LED (POST LED)
Figure 27. Diagnostic LED Placement Diagram
Revision 1.2
Intel order number: D41763-003
109