HYB25D256161CE Datasheet, PDF (15/72 Pages) Infineon Technologies AG – 16M x 16 Double Data Rate Graphics DRAM

HYB25D256161CE-[4/5]
256-Mbit Double Data Rate SGRAM
Functional Description
for a given configuration). The remaining (least significant) address bit(s) is (are) used to select the starting
location within the block. The programmed burst length applies to both Read and Write bursts.
3.2.2 Burst Type
Accesses within a given burst may be programmed to be either sequential or interleaved; this is referred to as the
burst type and is selected via bit A3. The ordering of accesses within a burst is determined by the burst length, the
burst type and the starting column address, as shown in Table 4.
Table 4
Burst
Length
2
4
8
Burst Definition
Starting Column Address
Order of Accesses Within a Burst
A2
A1
A0
Type = Sequential
Type = Interleaved
0
0-1
0-1
1
1-0
1-0
0
0
0-1-2-3
0-1-2-3
0
1
1-2-3-0
1-0-3-2
1
0
2-3-0-1
2-3-0-1
1
1
3-0-1-2
3-2-1-0
0
0
0
0-1-2-3-4-5-6-7
0-1-2-3-4-5-6-7
0
0
1
1-2-3-4-5-6-7-0
1-0-3-2-5-4-7-6
0
1
0
2-3-4-5-6-7-0-1
2-3-0-1-6-7-4-5
0
1
1
3-4-5-6-7-0-1-2
3-2-1-0-7-6-5-4
1
0
0
4-5-6-7-0-1-2-3
4-5-6-7-0-1-2-3
1
0
1
5-6-7-0-1-2-3-4
5-4-7-6-1-0-3-2
1
1
0
6-7-0-1-2-3-4-5
6-7-4-5-2-3-0-1
1
1
1
7-0-1-2-3-4-5-6
7-6-5-4-3-2-1-0
Notes
1. For a burst length of two, A1-Ai selects the two-data-element block; A0 selects the first access within the block.
2. For a burst length of four, A2-Ai selects the four-data-element block; A0-A1 selects the first access within the
block.
3. For a burst length of eight, A3-Ai selects the eight-data- element block; A0-A2 selects the first access within
the block.
4. Whenever a boundary of the block is reached within a given sequence above, the following access wraps
within the block.
3.2.3 Read Latency
The Read latency, or CAS latency, is the delay, in clock cycles, between the registration of a Read command and
the availability of the first burst of output data. The latency can be programmed 2, 2.5 and 3 clocks. CAS latency
of 1.5 is supported for DDR200 components only.
If a Read command is registered at clock edge n, and the latency is m clocks, the data is available nominally
coincident with clock edge n + m (see Figure 3)
Reserved states should not be used as unknown operation or incompatibility with future versions may result.
Datasheet
15
Rev.1.0, 2004-02