Rev. 1.2/Aug. 2008 26
1HY5PS561621BFP
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 sequ ential 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, inte rruption of a burst read or write operation is lim-
ited to two cases, reads interrupted by a read, or writes interrupted b y a writ e. T her efore the Burst Stop co m -
mand is not supported on DDR2 SDRAM devices.
Burst Length and Sequence
Note: Page length is a function of I/O organization and column addressing
Burst Length Starting Address (A2 A1 A0) Sequential Addressing (decimal) Interleave Addressing (decimal)
4
0 0 0 0, 1, 2, 3 0, 1, 2, 3
0 0 1 1, 2, 3, 0 1, 0, 3, 2
0 1 0 2, 3, 0, 1 2, 3, 0, 1
0 1 1 3, 0, 1, 2 3, 2, 1, 0
8
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, 0, 5, 6, 7, 4 1, 0, 3, 2, 5, 4, 7, 6
0 1 0 2, 3, 0, 1, 6, 7, 4, 5 2, 3, 0, 1, 6, 7, 4, 5
0 1 1 3, 0, 1, 2, 7, 4, 5, 6 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, 4, 1, 2, 3, 0 5, 4, 7, 6, 1, 0, 3, 2
1 1 0 6, 7, 4, 5, 2, 3, 0, 1 6, 7, 4, 5, 2, 3, 0, 1
1 1 1 7, 4, 5, 6, 3, 0, 1, 2 7, 6, 5, 4, 3, 2, 1, 0