Table 9. Post Progress Code Led Example; Table 10. Mrc Progress Codes - 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.
LED
Status
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 displayed to the diagnostic LEDs that show the execution point in the MRC
operational path at each step.
LED #
Upper
Nibble
Checkpoint
Lower
Nibble
MRC Progress Codes
Upper
Nibble
B0h
Lower
Nibble
Upper
Nibble
B1h
Lower
Nibble

Table 9. POST Progress Code LED Example

LED #3 LED #2 LED #1
8h (MSB) 4h
ON off
ON ON
8h (MSB) 4h
LED #3 LED #2 LED #1

Table 10. MRC Progress Codes

Diagnostic LED Decoder
LED 3 LED 2 LED 1
8h
4h 2h
(MSB)
8h
4h 2h
(MSB)
ON off ON
off off off
ON off ON
off off off
LED #0
2h 1h (LSB)
ON off
Upper Nibble: Ah
off off
Lower Nibble: Ch
2h 1h (LSB)
POST CODE: ACh
LED #0
LED 0
1h
Description
(LSB)
1h
(LSB)
ON
Detect DIMM population.
off
ON
Set DDR4 frequency.
ON
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