Reset
9.3.2
Primary FBD Link
When an EI occurs on the primary southbound FBD link a fast reset is started. This
starts a handshake procedure putting the DRAMs into self-refresh mode and resetting
the AMB. Fast reset does not reset the PLL, sticky flops, and sticky configuration
registers.
9.4
Details
Reset details and sequences will be released in a future revision of this document.
9.4.1
Cold Power-Up Reset Sequence
1. 1.5 V, 1.8 V and 3.3 V power supplies comes up
• RESET# asserted low while power supplies are coming up
• CKE’s are low upon 1.8 V power up
2. BIOS queries SPD on all the FBDs on the channel to determine operating conditions
— channel frequency, compatible DIMMs, DRAM and AMB parameters
3. Clocks up and stable at required frequency
• Reference Clocks (SCK/SCK) should be stable at least 1ms before RESET#
deasserted for designs with PLL running independent of RESET#
• DRAM clocks (CLK/CLK) may be toggling at this time
4. RESET# deasserted high
• CKE’s to DRAMs remain low
5. No transactions for at least 200 us after RESET# deasserted for designs with PLL’s
tied to RESET#
• No SMBus or in-band activity during this period
• DRAM clocks should be stable at this time
6. AMB parameters critical for robust link initialization are programmed via SMBus
• Architected link registers
— LINKPARNXT: link frequency - Note: some AMBs may use this write to trigger
PLL init
— FBDSBCFGNXT: SB transmitter drive strength, de-emphasis setting and pass-
thru mode
— FBDNBCFGNXT:NB transmitter drive strength, de-emphasis setting and pass-
thru mode
— FBDBLTO:if NB lanes are to be deconfigured
• Personality Bytes from SPD needed for link initialization
— PERSBYTE[5:0]NXT:
In the AMB, these match:
— SPDPAR01NXT: various FBD IO implementation specific controls
— SPDPAR23NXT:various FBD IO implementation specific controls
— SPDPAR45NXT
— remaining Personality bytes are not required for link init and may be loaded
over the high speed FBD configuration register accesses
Intel® 6400/6402 Advanced Memory Buffer Datasheet
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INTEL [ INTEL ]
