W949D6DB Datasheet, PDF (41/60 Pages) Winbond – Standard Self Refresh Mode

W949D6DB / W949D2DB
8.6.13 Interrupting Write to Precharge
Data for any WRITE burst may be truncated by a subsequent PRECHARGE command as shown in
below figure. Note that only data-in pairs that are registered prior to the tWR period are written to the
internal array, and any subsequent data-in should be masked with DM, as shown in below figure.
Following the PRECHARGE command, a subsequent command to the same bank cannot be issued
until tRP is met.
CK
CK
Command
Address
WRITE
BA,Col b
NOP
DQS
t_DQSSmax
DQ
DI b
DM
NOP
NOP
t_WR
*2
PRE
BA a (or all)
*1
*1
*1
1) Dl b = Data in to column b.
2) An interrupted burst of 4, 8 or 16 is shown, 2 data elements are written.
3) t_WR is referenced from the positive clock edge after the last desired Data In pair.
4) A10 is LOW with the WRITE command (Auto Precharge is disabled)
5) *1 = can be Don't Care for programmed burst length of 4
6) *2 = for programmed burst length of 4, DQS becomes Don't Care at this point
NOP
*1
= Don't Care
8.7 Precharge
The PRECHARGE command is used to deactivate the open row in a particular bank or the open row in
all banks. The bank(s) will be available for a subsequent row access a specified time (tRP) after the
PRECHARGE command is issued.
Input A10 determines whether one or all banks are to be precharged. In case where only one bank is to
be precharged, inputs BA0, BA1 select the bank. Otherwise BA0, BA1 are treated as “Don’t Care”.
Once a bank has been precharged, it is in the idle state and must be activated prior to any READ or
WRITE command being issued. A PRECHARGE command will be treated as a NOP if there is no open
row in that bank, or if the previously open row is already in the process of precharging.
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Publication Release Date: Oct. 08, 2014
Revision: A01-003