Table 56. Post Progress Code Led Example - Intel S5500WB12V Specification

Appendix A: POST Code LED Decoder
In the following example, the BIOS sends a value of ACh to the diagnostic LED decoder. The
LEDs are decoded as follows:
LEDs
MSB
LED #7
8h
Status
ON
Results
1
Upper nibble bits = 1010b = Ah; Lower nibble bits = 1100b = Ch; the two are concatenated
as ACh.
90

Table 56. POST Progress Code LED Example

Upper Nibble LEDs
LED #6 LED #5
4h 2h
OFF ON
0 1
Ah
Intel order number E53971-008
LED #4 LED #3
1h 8h
OFF ON
0 1
Intel® Server Board S5500WB TPS
Lower Nibble LEDs
LED #2 LED #1
4h 2h
ON OFF
1 0
Ch
Revision 1.9
LSB
LED #0
1h
OFF
0