12

Rev 0.7

64Mb Low Power DDR SDRAM

Advanced

Essential Functionality for DDR SDRAM

The essential functionality that is required for the DDR SDRAM device is described in this chapter

Burst Read Operation

Burst Read operation in DDR SDRAM is in the same manner as the SDRAM such that the burst read command is issued by asserting

inputs (A0~A9) determine the starting address for the Burst. The Mode Register sets type of burst(Sequential or interleave) and burst

length(2, 4, 8, 16). The first output data is available after the CAS Latency from the READ command, and the consecutive data are

presented on the falling and rising edge of Data Strobe(DQS) adopted by DDR SDRAM until the burst length is completed.

0

1

2

3

4

5

6

7

8

CK

CK

Command

NOP

NOP

NOP

NOP

NOP

NOP

NOP

NOP

READ A

Preambel

Postamble

Dout 0 Dout 1 Dout 2 Dout 3

CAS Latency=3

DQS

DQs

Figure.5 Burst read operation timing

< Burst Length=4, CAS Latency=3 >