Table 5. Post Progress Code Led Example - Intel P4304XXMFEN2 Service Manual

Intel ® Server Chassis P4304XXMFEN2/P4304XXMUXX Product Family System Integration and Service Guide
In the following example, the BIOS sends a value of ACh to the diagnostic LED decoder. The LEDs are
decoded as follows:
Note: Diagnostic LEDs are best read and decoded when viewing the LEDs from the back of the system.
MSB
LEDs
LED #7
8h
Status ON
1
Results
Ah
Upper nibble bits = 1010b = Ah; Lower nibble bits = 1100b = Ch; the two are concatenated as ACh
Early POST Memory Initialization MRC Diagnostic Codes
Memory Initialization at the beginning of POST includes multiple functions, such as: discovery, channel
training, validation that the DIMM population is acceptable and functional, initialization of the IMC and other
hardware settings, and initialization of applicable RAS configurations.
The MRC Progress Codes are displays to the diagnostic LEDs that show the execution point in the MRC
operational path at each step.
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Table 5. POST Progress Code LED Example

Upper Nibble AMBER LEDs
LED #6 LED #5
4h 2h
OFF ON
0 1
Lower Nibble GREEN LEDs
LED #4 LED #3
1h 8h
OFF ON ON
0 1 1
Ch
LED #2 LED #1 LED #0
4h 2h
OFF OFF
0 0
LSB
1h