Appendix C: Post Code Diagnostic Led Decoder; Figure 29. Diagnostic Led Placement Diagram; Table 46. Post Progress Code Led Example - Intel S5000XVNSATA Specification

Intel® Workstation Board S5000XVN TPS

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 workstation board. To assist in troubleshooting a system hang during the
POST process, you can use the Diagnostic LEDs to identify the last POST process 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
A. Status LED
B. ID LED
C. MSB LED (POST LED)
In the following example, the BIOS sends a value of ACh to the diagnostic LED decoder. The
LEDs are decoded as follows:
Red bits = 1010b = Ah
Green bits = 1100b = Ch
Since the red bits correspond to the upper nibble and the green bits correspond to the lower
nibble, the two are concatenated as ACh.
LEDs Red
ACh 1
Result Amber
MSB
Revision 1.5
B D F
C E

Figure 29. Diagnostic LED Placement Diagram

Table 46. POST Progress Code LED Example

8h 4h
Green Red
1 0
Green
Bit 2
Intel order number: D66403-006
Appendix C: POST Code Diagnostic LED Decoder
D. Bit 2 LED (POST LED)
E. Bit 1 LED (POST LED)
F. LSB LED (POST LED)
2h
Green Red
1 1 0
Red
Bit 1
AF001036
1h
Green Red Green
0 0
Off
LSB
87