HD6413002 Datasheet, PDF (167/700 Pages) Renesas Technology Corp – High-performance single-chip microcontroller

2CAS and 2WE Modes: The CAS/WE bit in RFSHCR can select two control modes for 16-bit-
wide DRAM: one using UCAS and LCAS; the other using UW and LW. These DRAM pins
correspond to H8/3002 pins as shown in table 7-6.
Table 7-6 DRAM Pins and H8/3002 Pins
H8/3002 Pin
HWR
LWR
RD
CS₃
CAS/WE = 0 (2WE mode)
UW
LW
CAS
RAS
DRAM Pin
CAS/WE = 1 (2CAS mode)
UCAS
LCAS
WE
RAS
Figure 7-5 (1) shows the interface timing for 2WE DRAM. Figure 7-5 (2) shows the interface
timing for 2CAS DRAM.
Read cycle
Write cycle*
Refresh cycle
ø
Address
bus
CS ₃
(RAS )
RD
(CAS )
HWR
(UW )
LWR
(LW )
RFSH
Row
AS
Note: * 16-bit access
Column
Row
Column
Area 3 top address
152