PRE Command Timing (TC_PRE_0_0_0_MCHBAR) – Offset E000 - 1.3 - ID:767625 | 12th Generation Intel® Core™ Processors Datasheet Volume 2 of 2

12th Generation Intel® Core™ Processors Datasheet Volume 2 of 2

ID	Date	Version	Classification
767625	07/13/2023		Public

PRE Command Timing (TC_PRE_0_0_0_MCHBAR) – Offset E000

DDR timing constraints related to PRE commands

Bit Range	Default	Access	Field Name and Description
63	0h	RO	Reserved
62:59	0x2	RW	Derating Extensions (derating_ext) Holds LPDDR timing parameters derating tRAS, tRRD, tRP and tRCD in tCK (WCK for LPDDR5) cycles. When LPDDR is hot, this value is added to the appropriate timing parameters. For non LP devices program the field to 0. Supported range is 0-4.
58:51	0x8	RW	tRCD Timing Parameter (tRCD) Holds DDR timing parameter tRCD ACT to CAS (RD or WR) same bank minimum delay in tCK (WCK for LPDDR5) cycles. Supported range is 8-59.
50:42	0x1C	RW	tRAS Timing Parameter (tRAS) Holds DDR timing parameter tRAS. ACT to PRE same bank minimum delay in tCK (WCK for LPDDR5) cycles. For DDR/LPDDR Supported range is 28-136
41:32	0x18	RW	tWRPRE Timing Parameter (tWRPRE) Holds DDR timing parameter tWRPRE. WR to PRE same bank minimum delay in tCK (WCK for LPDDR5) cycles. Supported range is 18-200.
31:24	0h	RO	Reserved
23:20	0x4	RW	tPPD Timing Parameter (tPPD) Holds DDR timing parameter tPPD. PRE/PREALL to PRE/PREALL (same rank) minimum delay in tCK (WCK for LPDDR5) cycles. Supported range is 4-7. Note this register is not used in DDR5;
19:13	0x6	RW	tRDPRE Timing Parameter (tRDPRE) Holds DDR timing parameter tRDPRE. RD to PRE same bank minimum delay in tCK (WCK for LPDDR5) cycles. Supported range is 4-32.
12:8	0x0	RW	tRPab_ext Timing Parameter (tRPab_ext) Holds the value of tRPab-tRPpb for LPDDR in tCK (WCK for LPDDR5) cycles. LPDDR technologies requires a longer time from PREALL to ACT vs. PRE to ACT, the offset between the two should be programmed to this field. When using DDR4 this field should be programmed to 0. For LPDDR4 the following restrictions apply: For single/dual rank sub channels tRP-tRPab_ext > 6. For three/four ranks sub channels tRP-tRPab_ext > 8. Supported range is 0-6.
7:0	0x8	RW	tRP Timing Parameter (tRP) Holds DDR timing parameter tRP (and tRCD). PRE to ACT same bank minimum delay in tCK (WCK for LPDDR5) cycles. ACT to CAS (RD or WR) same bank minimum delay in tCK (WCK for LPDDR5) cycles. Supported range is 8-60.