Appendix E: POST Code Diagnostic LED Decoder
Intel® Server Board S2600CW Family TPS
Revision 2.4
176
Appendix E: 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 sequence of eight amber diagnostic LEDs. The POST
codes are divided into two groups of LEDs as shown in the figure below.
The diagnostic LED #7 is labeled as “MSB”, and the diagnostic LED #0 is labeled as “LSB”.
Figure 33. POST Code Diagnostic LED Decoder
A – System Status LED
B – System ID LED
LSB 1 2 3 4 5 6 MSB – Diagnostic LED
In the following example, the BIOS sends a value of ACh to the diagnostic LED decoder. The
LEDs are decoded as follows.