W981216AH Datasheet, PDF (14/44 Pages) Winbond – 2M x 16 bit x 4 Banks SDRAM

W981216AH
2M x 16 bit x 4 Banks SDRAM
No Operation Command
The No Operation Command should be used in cases when the SDRAM is in a idle or a wait state to prevent the 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.
Deselect Command
The Deselect Command performs the same function as a No Operation Command. Deselect Command occurs when CS is brought
high, the RAS, CAS, and WE signals become don't cares.
Clock Suspend Mode
During normal access mode, CKE must be held high enabling the clock. When CKE is registered low while at least one of the
banks is active, Clock Suspend Mode is entered. The Clock Suspend mode deactivates the internal clock and suspends any
clocked operation that was currently being executed. There is a one clock delay between the registration of CKE low and the
time at which the SDRAM operation suspends. While in Clock Suspend mode, the SDRAM ignores any new commands that are
issued. The Clock Suspend mode is exited by bringing CKE high. There is a one clock cycle delay from when CKE returns high
to when Clock Suspend mode is exited.
Revision 1.0
- 14 -
Publication Release Date: March, 1999