EtronTech
A8
0
0
1
A7
0
1
X
Test Mode
normal mode
Vendor Use Only
Vendor Use Only
EM638165
•
Test Mode field (A8~A7)
These two bits are used to enter the test mode and must be programmed to "00" in normal
operation.
•
Write Burst Length (A9)
This bit is used to select the burst write length.
A9
0
1
9
Write Burst Length
Burst
Single Bit
No-Operation command
(RAS# = "H", CAS# = "H", WE# = "H")
The No-Operation command is used to perform a NOP to the SDRAM which is selected (CS#
is Low). This prevents unwanted commands from being registered during idle or wait states.
10
Burst Stop command
(RAS# = "H", CAS# = "H", WE# = "L")
The Burst Stop command is used to terminate either fixed-length or full-page bursts. This
command is only effective in a read/write burst without the auto precharge function. The terminated
read burst ends after a delay equal to the CAS# latency (refer to the following figure). The
termination of a write burst is shown in the following figure.
T0
T1
T2
T3
T4
T5
T6
T7
T8
CLK
COMMAND
READ A
NOP
NOP
NOP
Burst Stop
NOP
NOP
NOP
NOP
The burst ends after a delay equal to the CAS# latency.
CAS# latency=2
tCK2, DQ's
CAS# latency=3
tCK3, DQ's
DOUT A0
DOUT A1
DOUT A2
DOUT A3
DOUT A0
DOUT A1
DOUT A2
DOUT A3
Termination of a Burst Read Operation
(Burst Length
¡ Ö
CAS# Latency = 2, 3)
4,
T0
CLK
T1
T2
T3
T4
T5
T6
T7
T8
COMMAND
NOP
WRITE A
NOP
NOP
Burst Stop
NOP
NOP
NOP
NOP
CAS# latency= 2, 3
DQ's
DIN A0
DIN A1
DIN A2
don't care
Input data for the Write is masked.
Termination of a Burst Write Operation
(Burst Length = X, CAS# Latency = 1, 2, 3)
Preliminary
13
Rev 0.6
Feb. 2001
ETRON [ ETRON TECHNOLOGY, INC. ]
