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SDRAM




 

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, SDRAM ( READ, WRITE), . , (ACTIVATE) ( BA0-BA1 4- ) ( A0-A12, , 512- SDRAM 213 = 8192).

() (PRECHARGE), , . , (Row Active Time, tRAS).

- , . , (Row Cycle Time, tRC).

, SDRAM - ( SDRAM) . , SDRAM , (Row-to-Row Delay, tRRD). , .

/ :

, . , ( ACTIVATE) (READ) (WRITE) , , (RAS#-to-CAS# Delay, tRCD).

, , tRCD, READ ( ACTIVATE) . SDRAM (Burst) . , READ (WRITE) ( ) , , ( , 8 ). , READ WRITE, (Burst Length) 2, 4 8 ( () Full-Page Burst, BURST TERMINATE ). , DDR DDR2 Burst Length 2 4 , , SDR/DDR/DDR2 SDRAM.

, , . (READ), (Read with Auto-Precharge, RD+AP). , (PRECHARGE), .

READ, , , , , . CAS# (CAS# Latency, tCL). ( ) - , ( 1 SDR, 2 DDR/DDR2).

. (WRITE) (Write with Auto-Precharge, WR+AP). WRITE/WR+AP . , . . -, , , WRITE/WR+AP, , , . -, CAS# (tCL) , (Write Recovery Time, tWR). , , PRECHARGE. , , (Write-to-Read Delay, tWTR).

2.

/ , , PRECHARGE (, , , .. RD+AP WR+AP). , , (Row Precharge Time, tRP). , .. , .

 

 

, , : tCL-tRCD-tRP-tRAS ( ( ACTIVATE PRECHARGE, tRAS)), . (, 2-2-2-5 2.5-3-3-7 DDR; 3-3-3-9, 4-4-4-12 5-5-5-15 DDR2) .

, (, tRCD tCL, tRAS - ), , . , CAS# (tCL), , tRCD tRP ( , ).

 





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