【關鍵字】DDR，時序，建立時間，保持時間，眼圖，邏輯分析儀，示波器
【摘要】 DDR全名為Double Data Rate SDRAM ，簡稱為DDR。現在市場上的DDR已經發展到了DDR II，速度可以支持到667MT/s。FBD（Fully Buffered DIMM）也即將在市場上推出，速度更快。DDR總線走線數量多，速度快，操作復雜，容易出現問題，給測試和分析帶來了很高的挑戰。本文對DDR總線的失效情況進行了分析，總結一些實踐經驗，給出了測試分析的一些思路和方法。
【Key Words】 DDR, Timing, Setup Time, Hold Time, Eye Diagram, Logic Analyzer, Oscilloscope
【Abstract】SDRAM (Synchronous Dynamic Random Access Memory) is a critical component of computers and other electrical equipments. About several years ago, a new type of SDRAM,called DDR(Double Data Rate) was introduced,which memory clocks is on both edges. DDR II is the second generation of memory technologies,and it has four different form factors for more mainstream produces such as DIMM, SO-DIMM, Mini DIMM, Micro DIMM,and the speed is up 667MT/s.There are more 100 traces in DDR bus,and it is difficult to debug them.This article classifies the error types and provides some debugging method combining some experience.
DDR總線概覽
DDR全名為Double Data Rate SDRAM ，簡稱為DDR。現在市場上的DDR已經發展到了DDR II，速度可以支持到667MT/s。FBD（Fully Buffered DIMM）也即將在市場上推出，速度更快。DDR I和DDR II對比參考表1。