11
1Gbit (32Mx32bit) Mobile SDR Memory
H55S1G(2/3)2MFP Series
PRECHARGE
The PRECHARGE command is used to deactivate the open row in a particular bank or the open row in all banks.
Another command to the same bank (or banks) being precharged must not be issued until the precharge time (tRP) is
completed.
If one bank is to be precharged, the particular bank address needs to be specified. If all banks are to be precharged,
A10 should be set high along with the PRECHARGE command. If A10 is high, BA0 and BA1 are ignored. 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.
The below figure shows in case of 2KByte page size. If the page size is 4KByte, A0~A12 are provided.
CKE
(High)
A10 defines the precharge
mode when a precharge
command, a read command
or a write command is
issued.
CS
RAS
If A10 = High when a
precharge command is
issued, all banks are
precharged.
CAS
WE
If A10 = Low when a
precharge command is
issued, only the bank that is
selected by BA1/BA0 is
precharged.
A0~A9
A11~A13
If A10 = High when read or
write command, auto-
precharge function is
enabled.
A10
While A10 = Low, auto-
precharge function is
disabled.
BA0,1
BA
Bank Address
Don't Care
PRECHARGE command
AUTO PRECHARGE
Auto Precharge is a feature which performs the same individual bank precharge function as described above, but with-
out requiring an explicit command.
This is accomplished by using A10 (A10=high), to enable auto precharge in conjunction with a specific Read or Write
command. This precharges the bank/row after the Read or Write burst is complete.
Auto precharge is non persistent, so it should be enabled with a Read or Write command each time auto precharge is
desired. Auto precharge ensures that a precharge is initiated at the earliest valid stage within a burst.
The user must not issue another command to the same bank until the precharge time (tRP) is completed.
Rev 1.2 / Jun. 2008
39
HYNIX [ HYNIX SEMICONDUCTOR ]
