Address Multiplexing: When area 2 or area 3 is designated as DRAM space, address
multiplexing is always performed in accesses to DRAM. This enables DRAM, which requires row
and column address multiplexing, to be connected to the SH7750 Series without using an external
address multiplexer circuit. Any of the five multiplexing methods shown below can be selected,
by setting bits AMXEXT and AMX2–0 in MCR for area 2 or 3 DRAM. The relationship between
the AMXEXT and AMX2–0 bits and address multiplexing is shown in table 13.14. The address
output pins subject to address multiplexing are A17 to A1. The address signals output by pins A25
to A18 are undefined.
Table 13.14 Relationship between AMXEXT and AMX2–0 Bits and Address Multiplexing
Setting
AMXEXT
AMX2
AMX1
0
0
0
1
1
0
Other settings
Rev. 4.0, 04/00, page 336 of 850
Number
of Column
Address
AMX0
Bits
Output Timing
0
8 bits
Column address
Row address
1
9 bits
Column address
Row address
0
10 bits
Column address
Row address
1
11 bits
Column address
Row address
0
12 bits
Column address
Row address
Reserved
—
External Address Pins
A1–A13
A14
A15
A1–A13
A14
A15
A9–A21
A22
A23
A1–A13
A14
A15
A10–A22
A23
A24
A1–A13
A14
A15
A11–A23
A24
A25
A1–A13
A14
A15
A12–A24
A25
A15
A1–A13
A14
A15
A13–A25
A14
A15
—
—
—
A16
A17
A16
A17
A24
A25
A16
A17
A25
A17
A16
A17
A16
A17
A16
A17
A16
A17
A16
A17
A16
A17
—
—