Datasheet

CK
CK
Command WRITE
NOP NOP NOP PRE NOP
Address
BA,Col b
BA,Col n
BA
a(or
all)
DQS
DQ
tDQSSmax
t
WR
*2
DI b
DM
1) Dl b = Data in to column b.
*1 *1 *1 *1
= Don't Care
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
Figure 31 — Interrupting Write to Precharge
7.7 Precharge
The PRECHARGE command (see Figure 32) 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.
CK
CK
CKE
CS
RAS
CAS
WE
Address
A10
BA0,BA1
(High)
All Banks
One Bank
BA
= Don't Care
BA=BANK Address
(if A10 = L,otherwise Don't Care)
Figure 32 — Precharge command
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.
AS4C16M16MD1
256Mb MOBILE DDR SDRAM
Confidential
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Ver.1.1 Oct.2015