Intel® Server Board S5500WB TPS Appendix A: POST Code LED Decoder
Revision 1.3
Intel order number E53971-004
89
In the following example, the BIOS sends a value of ACh to the diagnostic LED decoder. The
LEDs are decoded as follows:
Table 55. POST Progress Code LED Example
Upper Nibble LEDs Lower Nibble LEDs
MSB LSB
LED #7 LED #6 LED #5 LED #4 LED #3 LED #2 LED #1 LED #0
LEDs
8h 4h 2h 1h 8h 4h 2h 1h
Status
ON OFF ON OFF ON ON OFF OFF
1
0
1
0
1 1
0 0
Results
Ah Ch
Upper nibble bits = 1010b = Ah; Lower nibble bits = 1100b = Ch; the two are concatenated
as ACh.