SH7211 Datasheet, PDF (267/1228 Pages) Renesas Technology Corp – 32-Bit RISC Microcomputer SuperHTM RISC engine Family

Section 8 Bus State Controller (BSC)
8.5.6 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 RASL, CASL, RD/WR, DQMUL,
DQMLL, CKE, CS2, and CS3. All the signals other than CS2 and 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 16 bits
only.
Burst read/single write (burst length 1) and burst read/burst write (burst length 1) are supported as
SDRAM operating mode.
Commands for SDRAM can be specified by RASL, CASL, 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 DQMUL 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 8.5.1, Endian/Access Size and Data Alignment.
Figure 8.13 shows an example of the connection of the SDRAM with the LSI.
Rev. 2.00 May. 08, 2008 Page 243 of 1200
REJ09B0344-0200