w942508bh Winbond Electronics Corp America, w942508bh Datasheet - Page 21

• Manufacturer Part Number: w942508bh
• Manufacturer: Winbond Electronics Corp America

10. No-Operation Command
11. Burst Read Stop Command
12. Device Deselect Command
13. Auto Refresh Command
14. Self Refresh Entry Command
15. Self Refresh Exit Command
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.
( 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.
( 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.
( 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 t
command is used, all banks must be in the idle state.
( 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.
(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 t
( RAS = "H", CAS = "H", WE = "H")
The No-Operation command simply performs no operation (same command as Device Deselect).
XSNR
(t
XSRD
for Read Command) from the end of this command.
REF
from the end of the Auto Refresh command. When the Auto Refresh
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Publication Release Date: March 19, 2002
W942508BH
Revision A1