This document summarizes the key aspects of a DDR2 SDRAM controller, including: 1) It describes the differences between DDR1 and DDR2 memory technologies, such as lower power consumption and higher data rates in DDR2. 2) It provides a block diagram of the main components and I/O signals of a DDR2 SDRAM controller. 3) It explains the basic functionality of a DDR2 SDRAM controller, including initialization, refresh operations, and read and write operations.

1. DDR2 SDRAM Controller By Pramod K Roshan M Titus Subash John Varun S

4. DDR1 vs. DDR2 Power consumption 2.5V 1.5V Reduces memory system power demand Data rate (MT/s per pin) 333 400 667 800 533 667 800 1066 Migration to higher data bandwidth Chip densities Up to 1Gb Up to 4Gb High-density components enable large memory subsystems with fewer chip counts Prefetch buffers 2 4 Enables faster clock rates Internal banks 4 4 and 8 1Gb and higher density DDR2 devices have 8 banks for better performance

5. Block Diagram Micron 512Mb DDR2 SDRAM ODT CKE CK CK# CS# RAS# CAS# WE# A0 – A13 BA0,BA1 DQ0 - DQn DQS DM

9. State Diagram

13. Fig. Refresh mode

15. Fig. Power down mode

16. Table 1. Truth Table - DDR2 commands

18. Fig. Mode Register

19. READ operation Fig 1. Simple Read operation

20. Fig 2. Consecutive Read Bursts Fig 3. Nonconsecutive Read Bursts

21. Fig 4. Read followed by precharge command

22. Fig. Read with AutoPrecharge

23. WRITE operation Fig. Simple Write operation

24. Fig. Consecutive Write operation Fig. Nonconsecutive Write operation

25. Fig. Write followed by a precharge command

26. Fig. Write with autoprecharge