Renesas SH7781 - Manual (Page 487)

12. DDR2-SDRAM Interface (DBSC2)
Rev.1.00 Jan. 10, 2008 Page 457 of 1658
REJ09B0261-0100
Section 12 DDR2-SDRAM Interface (DBSC2)
The DDR2-SDRAM interface (DBSC2) controls the DDR2-SDRAM.
12.1 Features
• Supports 32-bit and 16-bit external data bus widths
• Supports from DDR2-600 (controller operation at 300 MHz) to DDR2-400 (controller
operation at 200 MHz)
• Connects to 64-bit SuperHyway internal bus
• Supports 1:1 clock ratio between SuperHyway clock and DDR clock
• Queue provided for interface with SuperHyway
• During power-on reset, pin MODE8 can be used to switch between big- and little-endian
• Supports 4-bank and 8-bank DDR2-SDRAMs
• Supports sequential mode with burst length 4
• Supports Additive Latency (AL) of 0 only
• Supports differential data strobe signal (DQS, DQS)
Note: RDQS is not supported.
• Supports self-refresh
• Supports power supply backup mode
• Supported DDR2-SDRAM addresses × bit widths (total capacity) are as follows.
For details, refer to tables 12.12 through 12.19.
(When using 8-bank products, please refer to section 12.5.8, Important Information Regarding
Use of 8-Bank DDR2-SDRAM Products.)
⎯ DDR2-SDRAM data bus width: 32 bits
• Two 256 Mbits (16M × 16 bits) connected in parallel (total capacity = 512 Mbits)
• Four 256 Mbits (32M × 8 bits) connected in parallel (total capacity = 1 Gbit)
• Two 512 Mbits (32M × 16 bits) connected in parallel (total capacity = 1 Gbit)
• Four 512 Mbits (64M × 8 bits) connected in parallel (total capacity = 2 Gbits)
• Two 1 Gbit (64M × 16 bits) connected in parallel (total capacity = 2 Gbits)
• Four 1 Gbit (128M × 8 bits) connected in parallel (total capacity = 4 Gbits)
• Two 2 Gbits (128M × 16 bits) connected in parallel (total capacity = 4 Gbits)
• Four 2 Gbits (256M × 8 bits) connected in parallel (total capacity = 8 Gbits)