EDE5104ABSE, EDE5108ABSE, EDE5116ABSE
Data Sheet E0323E81 (Ver. 8.1)
39
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 bits burst and 8bits burst modes only. For 8 bits 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-I SDRAM operation. Seamless burst read or write operations are supported.
Unlike DDR-I devices, interruption of a burst read or writes operation is limited to ready by Read or W rite by W rite at
the boundary of Burst 4. Therefore the burst stop command is not supported on DDR2 SDRAM devices.
[Burst Length and Sequence]
Burst lengt h Start i ng address (A 2, A1, A0) Sequential addressing (decimal) Interleave addressing (decim al )
000 0, 1, 2, 3 0, 1, 2, 3
001 1, 2, 3, 0 1, 0, 3, 2
010 2, 3, 0, 1 2, 3, 0, 1
4
011 3, 0, 1, 2 3, 2, 1, 0
000 0, 1, 2, 3, 4, 5, 6, 7 0, 1, 2, 3, 4, 5, 6, 7
001 1, 2, 3, 0, 5, 6, 7, 4 1, 0, 3, 2, 5, 4, 7, 6
010 2, 3, 0, 1, 6, 7, 4, 5 2, 3, 0, 1, 6, 7, 4, 5
011 3, 0, 1, 2, 7, 4, 5, 6 3, 2, 1, 0, 7, 6, 5, 4
100 4, 5, 6, 7, 0, 1, 2, 3 4, 5, 6, 7, 0, 1, 2, 3
101 5, 6, 7, 4, 1, 2, 3, 0 5, 4, 7, 6, 1, 0, 3, 2
110 6, 7, 4, 5, 2, 3, 0, 1 6, 7, 4, 5, 2, 3, 0, 1
8
111 7, 4, 5, 6, 3, 0, 1, 2 7, 6, 5, 4, 3, 2, 1, 0
Note: Page length is a function of I/O organization and column addressing
32M bits × 4 organization (CA0 to CA9, CA11); Page Length = 2048 bits
16M bits × 8 organization (CA0 to CA9); Page Length = 1024 bits
8M bits × 16 organization (CA0 to CA9); Page Length = 1024 bits