DDR4标准 JESD79_4

1. Scope ......................................................................................................................................................................... 1
2. DDR4 SDRAM Package Pinout and Addressing ....................................................................................................... 2
2.1 DDR4 SDRAM Row for X4,X8 and X16 ................................................................................................................2
2.2 DDR4 SDRAM Ball Pitch........................................................................................................................................2
2.3 DDR4 SDRAM Columns for X4,X8 and X16 ..........................................................................................................2
2.4 DDR4 SDRAM X4/8 Ballout using MO-207......................................................................................................... 2
2.5 DDR4 SDRAM X16 Ballout using MO-207.............................................................................................................3
2.6 Pinout Description ..................................................................................................................................................5
2.7 DDR4 SDRAM Addressing.....................................................................................................................................7
3. Functional Description ...............................................................................................................................................8
3.1 Simplified State Diagram ....................................................................................................................................8
3.2 Basic Functionality..................................................................................................................................................9
3.3 RESET and Initialization Procedure .....................................................................................................................10
3.3.1 Power-up Initialization Sequence .............................................................................................................10
3.3.2 Reset Initialization with Stable Power ......................................................................................................11
3.4 Register Definition ................................................................................................................................................12
3.4.1 Programming the mode registers .............................................................................................................12
3.5 Mode Register ......................................................................................................................................................13
4. DDR4 SDRAM Command Description and Operation ............................................................................................. 24
4.1 Command Truth Table ..........................................................................................................................................24
4.2 CKE Truth Table ...................................................................................................................................................25
4.3 Burst Length, Type and Order ..............................................................................................................................26
4.3.1 BL8 Burst order with CRC Enabled .........................................................................................................26
4.4 DLL-off Mode & DLL on/off Switching procedure ................................................................................................27
4.4.1 DLL on/off switching procedure ...............................................................................................................27
4.4.2 DLL “on” to DLL “off” Procedure ..............................................................................................................27
4.4.3 DLL “off” to DLL “on” Procedure ..............................................................................................................28
4.5 DLL-off Mode........................................................................................................................................................29
4.6 Input Clock Frequency Change ............................................................................................................................30
4.7 Write Leveling.......................................................................................................................................................31
4.7.1 DRAM setting for write leveling & DRAM termination function in that mode ............................................32
4.7.2 Procedure Description .............................................................................................................................33
4.7.3 Write Leveling Mode Exit .........................................................................................................................34