Renesas SH7781 - Manual (Page 37)

1. Overview
Rev.1.00 Jan. 10, 2008 Page 7 of 1658
REJ09B0261-0100
Item Features
DDR2-SDRAM bus
controller (DBSC)
• A dedicated DDR2-SDRAM bus interface
⎯ Multi-bank support: Supports multi-bank (four banks) operation
⎯ Number of banks: Supports four or eight banks (however, no more
than four banks can be opened concurrently)
⎯ Selectable bus width: 32-/16-bit
⎯ Supports preceding precharging and activation
⎯ Burst length: Four (fixed)
⎯ Burst type: Sequential (fixed)
⎯ CAS latency: 2, 3, 4, 5, 6 cycles
• Auto-refresh mode
⎯ An average interval is selectable by a register setting. Preceding
refresh operations are performed when there are no pending
requests.
• Self-refresh mode
• Connectable memory capacity: Up to 1 Gbyte
⎯ With a 32-bit bus width
16 M x 16 bits (256 Mbits) x 2, 32 M x 16 bits (512 Mbits) x 2, 64 M x
16 bits (1 Gbit) x 2, 128 M x 16 bits (2 Gbits) x 2, 32 M x 8 bits (256
Mbits) x 4, 64 M x 8 bits (512 Mbits) x 4, 128 M x 8 bits (1 Gbit) x 4,
256 M x 8 bits (2 Gbits) x 4
⎯ With a 16-bit bus width
16 M x 16 bits (256 Mbits) x 1, 32 M x 16 bits (512 Mbits) x 1, 64 M x
16 bits (1 Gbit) x 1, 128 M x 16 bits (2 Gbits) x 1, 32 M x 8 bits (256
Mbits) x 2, 64 M x 8 bits (512 Mbits) x 2, 128 M x 8 bits (1 Gbit) x 2,
256 M x 8 bits (2 Gbits) x 2
• Big or little endian is selectable