SH7670 Datasheet, PDF (258/1292 Pages) Renesas Technology Corp – 32-Bit RISC Microcomputer SuperHTM RISC engine Family / SH7670 Series

Section 7 Bus State Controller (BSC)
7.5.5 SDRAM Interface
(1) SDRAM Direct Connection
The SDRAM that can be connected to this LSI is a product that has 11/12/13 bits of row address,
8/9/10 bits of column address, 4 or less banks, and uses the A10 pin for setting precharge mode in
read and write command cycles.
The control signals for direct connection of SDRAM are RAS, CAS, RD/WR, DQMUU,
DQMUL, DQMLU, DQMLL, CKE, and CS3. All the signals other than CS3 are common to all
areas, and signals other than CKE are valid when CS2 or CS3 is asserted. SDRAM can be
connected to up to 2 spaces. The data bus width of the area that is connected to SDRAM can be set
to 32 or 16 bits.
Burst read/single write (burst length 1) and burst read/burst write (burst length 1) are supported as
the SDRAM operating mode.
Commands for SDRAM can be specified by RAS, CAS, RD/WR, and specific address signals.
These commands supports:
• NOP
• Auto-refresh (REF)
• Self-refresh (SELF)
• All banks pre-charge (PALL)
• Specified bank pre-charge (PRE)
• Bank active (ACTV)
• Read (READ)
• Read with pre-charge (READA)
• Write (WRIT)
• Write with pre-charge (WRITA)
• Write mode register (MRS, EMRS)
The byte to be accessed is specified by DQMUU, DQMUL, DQMLU, and DQMLL. Reading or
writing is performed for a byte whose corresponding DQMxx is low. For details on the
relationship between DQMxx and the byte to be accessed, see section 7.5.1, Endian/Access Size
and Data Alignment.
Figures 7.12 to 7.13 show examples of the connection of the SDRAM with the LSI.
Rev. 1.00 Nov. 14, 2007 Page 232 of 1262
REJ09B0437-0100