M16C62_N Datasheet, PDF (532/621 Pages) Renesas Technology Corp – 16-BIT SINGLE-CHIP MICROCOMPUTER M16C FAMILY

External Buses
Mitsubishi microcomputers
M16C / 62 Group
SINGLE-CHIP 16-BIT CMOS MICROCOMPUTER
(1)4-Mbyte ROM and 128-Kbyte SRAM Connection Example
Figure 5.3.6 shows how to connect 4-Mbyte ROM and 128-Kbyte SRAM in microprocessor mode. Locate
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the 4-Mbyte ROM in the CS0 area that has been extended in memory space extension mode 2 and the
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128-Kbyte SRAM in the CS2 area.
CNVss ^CS0
CS1
BYTE ^CS2
CS3
A0 to A19
RD
WR
D0 to D7
M16C/62
A16 _A16
to _to
A0 _A0
CS2 _S1
CS0 _S2
RD _OE
WR _W
DQ1 ^D0
to ^to
DQ8 ^D7
128K bytes SRAM
CS3 _A21
CS2 _A20
CS1 _A19
A19 _A18
A17 to A0 _{A17 to A0}
CS0 _CE
DQ0 ^D0
to ^to
RD _OE
DQ7 ^D7
4M bytes ROM
Figure 5.3.6. 4-Mbyte ROM and 128-Kbyte SRAM Connection Example
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Connect CS0 to the 4-Mbyte ROM’s chip enable pin and CS1, CS2, and CS to the address pins A19, A20,
and A21, respectively. Connect the M16C’s A19 to the 4-Mbyte ROM’s A18, leaving the M16C’s A18
unused.
In the above diagram, an SRAM with two chip select signal inputs is used. When using memory with only
one chip select signal input, you need to have an external circuit to decode the address.
Addresses in 4-Mbyte ROM with regard to M16C settings are shown in Table 5.3.1.
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