r4f2426 Renesas Electronics Corporation., r4f2426 Datasheet - Page 271

• Manufacturer Part Number: r4f2426
• Description: 16-bit Single-chip Microcomputer H8s Family / H8s/2400 Series
• Manufacturer: Renesas Electronics Corporation.

6.8
In the H8S/2426R Group, external address space areas 2 to 5 can be designated as continuous
synchronous DRAM space, and synchronous DRAM interfacing performed. The synchronous
DRAM interface allows synchronous DRAM to be directly connected to this LSI. A synchronous
DRAM space of up to 8 Mbytes can be set by means of bits RMTS2 to RMTS0 in DRAMCR.
Synchronous DRAM of CAS latency 1 to 4 can be connected.
Note: The synchronous DRAM interface is not supported by the H8S/2426 Group and H8S/2424
6.8.1
Areas 2 to 5 are designated as continuous synchronous DRAM space by setting bits RMTS2 to
RMTS0 in DRAMCR. The relation between the settings of bits RMTS2 to RMTS0 and
synchronous DRAM space is shown in table 6.8. Possible synchronous DRAM interface settings
are and continuous area (areas 2 to 5).
Table 6.8
With continuous synchronous DRAM space, CS2, CS3, CS4 pins are used as RAS, CAS, WE
signal. The (OE) pin of the synchronous DRAM is used as the CKE signal, and the CS5 pin is
used as synchronous DRAM clock (SDRAMφ). The bus specifications for continuous
synchronous DRAM space conform to the settings for area 2. The pin wait and program wait for
the continuous synchronous DRAM are invalid.
Commands for the synchronous DRAM can be specified by combining RAS, CAS, WE, and
address-precharge-setting command (Precharge-sel) output on the upper column addresses.
RMTS2
0
1
Group.
Synchronous DRAM Interface
Setting Continuous Synchronous DRAM Space
RMTS1
0
1
0
1
Relation between Settings of Bits RMTS2 to RMTS0 and Synchronous DRAM
Space
RMTS0
1
0
1
0
1
0
1
Area 5
Normal space
Normal space
DRAM space
Continuous synchronous DRAM space
Mode settings of synchronous DRAM
Reserved (setting prohibited)
Continuous DRAM space
Area 4
Normal space
Normal space
DRAM space
Rev. 1.00 Sep. 19, 2008 Page 243 of 1270
Area 3
Normal space
DRAM space
DRAM space
Section 6 Bus Controller (BSC)
REJ09B0466-0100
Area 2
DRAM space
DRAM space
DRAM space