HY5PS1G821M Datasheet, PDF (28/79 Pages) Hynix Semiconductor – 1Gb DDR2 SDRAM(DDP)

1HY5PS12421(L)M
HY5PS12821(L)M
2.5.2 Burst Mode Operation
Burst mode operation is used to provide a constant flow of data to memory locations (write cycle), or from
memory locations (read cycle). The parameters that define how the burst mode will operate are burst
sequence and burst length. DDR2 SDRAM supports 4 bit burst and 8 bit burst modes only. For 8 bit burst
mode, full interleave address ordering is supported, however, sequential address ordering is nibble based for
ease of implementation. The burst type, either sequential or interleaved, is programmable and defined by the
address bit 3 (A3) of the MRS, which is similar to the DDR SDRAM operation. Seamless burst read or write
operations are supported. Unlike DDR devices, interruption of a burst read or write cycle during BL = 4 mode
operation is prohibited. However in case of BL = 8 mode, interruption of a burst read or write operation is lim-
ited to two cases, reads interrupted by a read, or writes interrupted by a write. Therefore the Burst Stop com-
mand is not supported on DDR2 SDRAM devices.
Burst Length and Sequence
Burst Length
4
8
Starting Address (A2 A1 A0)
000
001
010
011
000
001
010
011
100
101
110
111
Sequential Addressing (decimal)
0, 1, 2, 3
1, 2, 3, 0
2, 3, 0, 1
3, 0, 1, 2
0, 1, 2, 3, 4, 5, 6, 7
1, 2, 3, 0, 5, 6, 7, 4
2, 3, 0, 1, 6, 7, 4, 5
3, 0, 1, 2, 7, 4, 5, 6
4, 5, 6, 7, 0, 1, 2, 3
5, 6, 7, 4, 1, 2, 3, 0
6, 7, 4, 5, 2, 3, 0, 1
7, 4, 5, 6, 3, 0, 1, 2
Interleave Addressing (decimal)
0, 1, 2, 3
1, 0, 3, 2
2, 3, 0, 1
3, 2, 1, 0
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
Note: Page length is a function of I/O organization and column addressing
Rev. 0.2 / Oct. 2005
28