IC61C6416 Datasheet, PDF (32/80 Pages) Integrated Circuit Solution Inc – 64K X 16 HIGH-SPEED CMOS STATIC RAM

HYB18T256324F–[16/20/22]
256-Mbit DDR SGRAM
Functional Description
#,+
#,+
#OM
0!
./0
-23
./0
./0
!#
./0
2$
T₂₀
Figure 16 Mode Register Set Timing
T_{- 2$}
T_-2$2
-23-23COMMAND
0!02%!,,COMMAND
!#!NYOTHERCOMMANDAS2%!$
2$2%!$COMMAND
$ONgT#ARE
Table 19 MRS Timing Parameters for –1.6, –2.0 and –2.2 speed sorts
Parameter
Symbol
Limit Values
Unit
–1.6
–2.0
–2.2
min max min max min max
Mode Register Set cycle time
Mode Register Set to READ timing
t_MRD
5
—4
—4
—
t_CK
t_MRDR
15
—
12
—
12
—
t_CK
Notes
1, 2
1
1. This value of t_MRD applies only to the case where the
“DLL reset” bit is not activated.
2. t_MRD is defined from MRS to any other command as READ.
3.5.1 Burst length
Read and Write accesses to the GDDR3 Graphics RAM are burst oriented with burst length 4. This value must be
programmed using the Mode Register Set command (A0 .. A2). The burst length determines the number of column
locations that can be accessed for a given READ or WRITE command.
When a READ or WRITE command is issued, a block of columns equal to the burst length is effectively selected.
All accesses for that burst take place within this block if a boundary is reached. The block is uniquely selected by
A2-Ai where Ai is the most significant bit for a given configuration. The starting location within this block is
determined by the two least significant bits A0 and A1 which are set internally to the fixed value of zero each.
Reserved states should not be used, as unknow operation or incompatibility with future versions may result.
3.5.2 Burst type
Accesses within a given bank must be programmed to be sequential. This is done using the Mode Register Set
command (A3) . This device does not support the burst interleave mode.
Table 20 Burst Type
Burst Length
Starting Column address
4
A1 A0
xx
Order of accesses within the burst
Type = Sequential
0-1-2-3
The value applied at the balls A0 and A1 for the column address is “Don’t care”.
Data Sheet
32
Rev. 1.11, 04-2005
10292004-DOXT-FS0U