Intel® Server System M50CYP1UR Family System Integration and Service Guide
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Table 8. POST Progress Code LED Example
Upper nibble bits = 1010b = Ah; Lower nibble bits = 1100b = Ch; the two Hex Nibble values are combined to
create a single ACh POST Progress Code.
E.1 Early POST Memory Initialization MRC Diagnostic Codes
Memory initialization at the beginning of POST includes multiple functions: 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.
Table 9. MRC Progress Codes
Gather remaining SPD data
Program registers on the memory controller level
Evaluate RAS modes and save rank information
Program registers on the channel level
Perform the JEDEC defined initialization sequence
Train DDR4 ranks – Read DQ/DQS training
Train DDR4 ranks – Receive enable training
Train DDR4 ranks – Write DQ/DQS training
Train DDR4 ranks – DDR channel training done
Hardware memory test and init
Execute software memory init
Program memory map and interleaving
Program RAS configuration