HD6433044 Hitachi Semiconductor, HD6433044 Datasheet - Page 174

• Manufacturer Part Number: HD6433044
• Description: (HD64 Series) Hitachi Single-Chip Microcomputer
• Manufacturer: Hitachi Semiconductor

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 H8/3048 Series pins as shown in table 7-6.
Table 7-6 DRAM Pins and H8/3048 Series Pins
H8/3048 Series Pin
HWR
LWR
RD
CS
Figure 7-5 (1) shows the interface timing for 2WE DRAM. Figure 7-5 (2) shows the interface
timing for 2CAS DRAM.
ø
(
(
(
(
Note:
Address
bus
3
CS
RAS
RD
CAS
HWR
UW
LWR
LW
RFSH
AS
3
)
)
)
)
*
16-bit access
Figure 7-5 DRAM Control Signal Output Timing (1) (2WE Mode)
Row
Read cycle
CAS/WE = 0 (2WE Mode)
UW
LW
CAS
RAS
Column
Row
Write cycle
160
Column
DRAM Pin
*
CAS/WE = 1 (2CAS Mode)
UCAS
LCAS
WE
RAS
Area 3 top address
Refresh cycle