EtronTech
EM636165-XXI
1M x 16 SDRAM
6
Write and AutoPrecharge command (refer to the following figure)
(RAS# = "H", CAS# = "L", WE# = "L", A11 = “V”, A10 = "H", A0-A7 = Column Address)
The Write and AutoPrecharge command performs the precharge operation automatically after
the write operation. Once this command is given, any subsequent command can not occur within a
time delay of (burst length -1) + tWR + tRP(min.) . At full-page burst, only the write operation is
{
}
performed in this command and the auto precharge function is ignored.
T0
T1
T2
T3
T4
T5
T6
T7
T8
CLK
Bank A
Write A
COMMAND
NOP
NOP
NOP
NOP
NOP
NOP
NOP
AutoPrecharge
Activate
tDAL
CAS# latency=1
DIN
DIN
DIN
A
A
A
DIN A
DIN A
DIN A
0
0
0
1
1
1
*
*
*
t
, DQ's
CK1
tDAL
CAS# latency=2
, DQ's
t
CK2
tDAL
CAS# latency=3
, DQ's
t
CK3
Begin AutoPrecharge
Bank can be reactivated at completion of tDAL
tDAL= tWR + tRP
*
Burst Write with Auto-Precharge
(Burst Length = 2, CAS# Latency = 1, 2, 3)
7
Mode Register Set command
(RAS# = "L", CAS# = "L", WE# = "L", A11 = “V”, A10 = “V”, A0-A9 = Register Data)
The mode register stores the data for controlling the various operating modes of SDRAM. The
Mode Register Set command programs the values of CAS# latency, Addressing Mode and Burst
Length in the Mode register to make SDRAM useful for a variety of different applications. The
default values of the Mode Register after power-up are undefined; therefore this command must be
issued at the power-up sequence. The state of pins A0~A9 and A11 in the same cycle is the data
written to the mode register. One clock cycle is required to complete the write in the mode register
(refer to the following figure). The contents of the mode register can be changed using the same
command and the clock cycle requirements during operation as long as both banks are in the idle
state.
Preliminary
11
Rev. 1.1 Apr. 2005
ETRON [ ETRON TECHNOLOGY, INC. ]
