8
V54C365404VD(L) Rev. 0.9 September 2001
MOSEL VITELIC
V54C365404VD(L)
Burst Length and Sequence:
Burst
Length
Starting Address
(A2 A1 A0)
Sequential Burst Addressing
(decimal)
Interleave Bur st Addressing
(decimal)
2 xx0
xx1
0, 1
1, 0
0, 1
1, 0
4x00
x01
x10
x11
0, 1, 2, 3
1, 2, 3, 0
2, 3, 0, 1
3, 0, 1, 2
0, 1, 2, 3
1, 0, 3, 2
2, 3, 0, 1
3, 2, 1, 0
8 000
001
010
011
100
101
110
111
0 1 2 3 4 5 6 7
1 2 3 4 5 6 7 0
2 3 4 5 6 7 0 1
3 4 5 6 7 0 1 2
4 5 6 7 0 1 2 3
5 6 7 0 1 2 3 4
6 7 0 1 2 3 4 5
7 0 1 2 3 4 5 6
0 1 2 3 4 5 6 7
1 0 3 2 5 4 7 6
2 3 0 1 6 7 4 5
3 2 1 0 7 6 5 4
4 5 6 7 0 1 2 3
5 4 7 6 1 0 3 2
6 7 4 5 2 3 0 1
7 6 5 4 3 2 1 0
Full
Page
nnn Cn, Cn+1, Cn+2,..... not supported
Refresh Mode
SDRAM has two refresh mode s, Auto Refresh
and Self Refresh. Auto Refresh is similar to the CAS
-before-RAS refresh of c onv entional DRAMs. All of
banks must be precharged before applying any refresh mode. A n on-chip address counter increments
the word and the bank address es and no bank information is required fo r both refresh modes.
The chip ent ers the Auto Refresh mode, when
RAS
and CAS are held low and CKE and WE are
held high at a clock timing. The mode restores word
line after the refresh and no externalprecharge command is necess ary. A minimum tRC time is required
between two autom atic ref res hes in a burst refresh
mode. The same r ule applies to any access command after the a utomatic refresh operation.
The chip has an on-chip t im er and the Self Refresh mode is available. It enters the mode when
RAS
,CAS, and CKE are low and WE is high at a
clock tim ing. All of external control signals including
the clock are disabled. Returning CKE to high enables the clock and initiates the refresh exit operation. After the exit command, at least one t
RC
delay
is required prior to any access c ommand.
DQM Function
DQM has two functions for data I/O read and write
operations. During reads, w hen it turns to “high” at a
clock timing, data outputs are disabled and become
high impedance after t wo clock delay (DQM Data
Disable Latency t
DQZ
). It also provides a data mask
function for w rites. When DQM is activated, the w rite
operation at the next clock is prohibited (DQM Write
MaskLatency t
DQW
= zero clocks).
Suspend Mode
During normal access mode, CKE is held high enabling the clock. When CKE is low, it freezes the internal clock and extends data read and write
operations. One clock delay is required for mode entry and exit (Clock Suspend Latency t
CSL
).
Power Down
In order to reduce standby power consumption, a
power down mode is avail able. All banks must be
precharged and thenecessa ry Precharge delay (trp)
must occur before the SDRAM can enter the Power
Down mode. Once the Power Down mode is
initiated by holding CK E low, all of the receiver
circuits except CLK and CKE are gated off. The
Power D own mode does not perform any refresh
operations, therefore the device can’t remain in
Power Down mode longer than the Refresh period
(tref) of the device. Ex it from this mode is performed
by taking CKE “high”. One clock delay is required for
mode entry and exit.
Auto Precharge
Two methods are available to precharge
SDRAMs. In an automatic precharge mode, the
CAS timing accepts one extra address, CA10, to
determine whether the chip restores or not afte r the