HY5PS1G821M Datasheet, PDF (55/79 Pages) Hynix Semiconductor – 1Gb DDR2 SDRAM(DDP)

1HY5PS12421(L)M
HY5PS12821(L)M
2.11 No Operation Command
The No Operation command should be used in cases when the DDR2 SDRAM is in an idle or a wait state.
The purpose of the No Operation command (NOP) is to prevent the DDR2 SDRAM from registering any
unwanted commands between operations. A No Operation command is registered when CS is low with
RAS, CAS, and WE held high at the rising edge of the clock. A No Operation command will not terminate a
previous operation that is still executing, such as a burst read or write cycle.
2.12 Deselect Command
The Deselect command performs the same function as a No Operation command. Deselect command
occurs when CS is brought high at the rising edge of the clock, the RAS, CAS, and WE signals become
don’t cares.
Rev. 0.2 / Oct. 2005
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