W942508CH Datasheet, PDF (23/47 Pages) Winbond – 8M x 4 BANKS x 8 BIT DDR SDRAM

W942508CH
9. Extended Mode Register Set Command
( RAS = "L", CAS = "L", WE = "L", BS0 = "H", BS1 = "L", A0 to A12 = Register data)
The Extended Mode Register Set command can be implemented as needed for function
extensions to the standard (SDR-SDRAM). Currently the only available mode in EMRS is DLL
enable/disable, decoded by A0. The default value of the extended mode register is not defined;
therefore this command must be issued during the power-up sequence for enabling DLL. Refer
to the table for specific codes.
10. No-Operation Command
( RAS = "H", CAS = "H", WE = "H")
The No-Operation command simply performs no operation (same command as Device
Deselect).
11. Burst Read Stop Command
( RAS = "H", CAS = "H", WE = "L")
The Burst stop command is used to stop the burst operation. This command is only valid during
a Burst Read operation.
12. Device Deselect Command
( CS = "H")
The Device Deselect command disables the command decoder so that the RAS , CAS , WE and
Address inputs are ignored. This command is similar to the No-Operation command.
13. Auto Refresh Command
( RAS = "L", CAS = "L", WE = "H", CKE = "L", BS0, BS1, A0 to A12 = Don’t care)
The Auto Refresh command is used to refresh the row address provided by the internal refresh
counter. The Refresh operation must be performed 8192 times within 64ms. The next command
can be issued after tREF from the end of the Auto Refresh command. When the Auto Refresh
command is used, all banks must be in the idle state.
14. Self Refresh Entry Command
( RAS = "L", CAS = "L", WE = "H", CKE = "L", BS0, BS1, A0 to A12 = don’t care)
The Self Refresh Entry command is used to enter Self Refresh mode. While the device is in Self
Refresh mode, all input and output buffer (except the CKE buffer) are disabled and the Refresh
operation is automatically performed. Self Refresh mode is exited by taking CKE "high" (the Self
Refresh Exit command). During self refresh, DLLl is disable.
15. Self Refresh Exit Command
(CKE = "H", CS = "H" or CKE = "H", RAS = "H", CAS = "H")
This command is used to exit from Self Refresh mode. Any subsequent commands can be
issued after tXSNR (tXSRD for Read Command) from the end of this command.
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Publication Release Date: May 21, 2003
Revision A3