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DIFFERENCE between PRECHARGE and REFRESH in SDRAMs..........

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functionality of precharge (pre) command

can anyone explain the difference between.............

PRECHARGE and REFRESH in SDRAMs


thanks
 

difference between ddr precharge and refresh

for one address that a row is selected and we read the data and the in the next clk pulse if we have to select new address the previous row should be make disable .In this case precharge will take care. suggest me if i am not correct
thanks
 

orecharge and refresh

before read or write operation on SDRAM bank needs to be activeted, by issunig comand "active" the read or write comand, after read or write is complited, we can still issue another command read or write, but access should be in the same page. When we finish reading or writing from SDRAM or we need to do refresh than we issuing comand precharge (A10 specify is it only one bank or all) after command pre-charge SDRAM gets in to the idle mode.
In order to keep information in SDRAM we need to issue Refresh comand every 15,625uS or 4096 times every 64mS.
To make long story short
precharge to put SDRAM into IDLE
Refresh to refresh data inside SDRA


Regards,
 

why do we need to precharge for sdram

Precharge is the first operation in the initilization phase ....
if we want to open new Row then we need to close previous row to operate functionally well,b/c of this we do precharge operation

As in Dynamic Ram charge is stored onto a capacitor & since capacitor can store charge indefinitely we need to refresh operation.
2 types of Refresh operation are
a). Auto Refresh done by Controller
b). Self Refresh automatically done by Memory
Anmol

Added after 1 minutes:

anmolvlsi13 said:
Precharge is the first operation in the initilization phase ....
if we want to open new Row then we need to close previous row to operate functionally well,b/c of this we do precharge operation

As in Dynamic Ram charge is stored onto a capacitor & since capacitor can store charge indefinitely we need to refresh operation.
2 types of Refresh operation are
a). Auto Refresh done by Controller
b). Self Refresh automatically done by Memory
Anmol
Click to expand...
:idea:
 

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