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White Electronic Designs Corporation (508) 366-5151 www.whiteedc.com
WED9LC6416V
January 20001
Mode Register Set
L
X
OP CODE
Auto Refresh (CBR)
L
H
X
Precharge
Single Bank
L
H
L
X
BA
L
2
Precharge all Banks
L
H
L
X
H
Bank Activate
L
H
X
BA
Row Address
2
Write
L
H
L
X
BA
L
2
Write with Auto Precharge
L
H
L
X
BA
H
2
Read
L
H
L
X
BA
L
2
Read with Auto Precharge
L
H
L
H
X
BA
H
2
Burst Termination
L
H
L
X
3
No Operation
L
H
X
Device Deselect
H
X
Data Write/Output Disable
X
L
X
4
Data Mask/Output Disable
X
H
X
4
NOTES:
1. All of the SDRAM operations are defined by states of SDCE\, SDWE\, SDRAS\, SDCAS\, and BWE0-3 at the positive rising edge of the clock.
2. Bank Select (BA), if A12 (BA0) and A13 (BA1) select between different banks.
3. During a Burst Write cycle there is a zero clock delay, for a Burst Read cycle the delay is equal to the CAS latency.
4. The BWE has two functions for the data DQ Read and Write operations. During a Read cycle, when BWE goes high at a clock timing the data outputs are disabled
and become high impedance after a two clock delay. BWE also provides a data mask function for Write cycles. When it activates, the Write operation at the clock is
prohibited (zero clock latency).
Function
SDCE
SDRAS
SDCAS
SDWE
BWE
A12, A13
SDA10
Notes
A11-0
SDRAM COMMAND TRUTH TABLE
CLOCK FREQUENCY AND LATENCY PARAMETERS - 125MHz SDRAM
(Unit = number of clock)
Frequency
CAS
tRC
tRAS
tRP
tRRD
tRCD
tCCD
tCDL
tRDL
70ns
50ns
20ns
10ns
125MHz (8.0ns)
3
9
6
3
2
3
1
100MHz (10.0ns)
3
7
5
2
1
83MHz (12.0ns)
2
6
4
2
1
Latency
CLOCK FREQUENCY AND LATENCY PARAMETERS - 100MHz SDRAM
(Unit = number of clock)
Frequency
CAS
tRC
tRAS
tRP
tRRD
tRCD
tCCD
tCDL
tRDL
70ns
50ns
20ns
10ns
100MHz (12.0ns)
3
7
5
2
1
83MHz (12.0ns)
2
6
5
2
1
Latency
-10
-12
Parameter
Symbol
Min
Max
Min
Max
Units
Refresh Period (1,2)
tREF
—64
—
64
ms
NOTES:
1. 4096 cycles
2. Any time that the Refresh Period has been exceeded, a minimum of two Auto (CBR) Refresh commands must be given to "wake-up" the device.
REFRESH CYCLE PARAMETERS