M30622 Mitsubishi, M30622 Datasheet - Page 26

• Manufacturer Part Number: M30622
• Description: SINGLE-CHIP 16-BIT CMOS MICROCOMPUTER
• Manufacturer: Mitsubishi

Memory Space Expansion Functions
The data bank register is made up of the bank selection bits (bits 5 through 3) and the offset bit (bit 2). The
bank selection bits are used to set a bank number for accessing data lying between 40000
BFFFF
Figure 1.8.5 shows the memory location and chip select areas in expansion mode 2.
The area relevant to CS0 ranges from 40000
BFFFF
- CS1 only in accessing data. In fetching a program, bank 7 (111
area from C0000
data or to fetching a program.
In accessing an area irrelevant to CS0, a chip select signal CS3 (4000
27FFF
Figure 1.8.6 shows an example of connecting the MCU with a 4-M byte ROM and to a 128-K byte SRAM.
Connect the chip select of 4-M byte ROM with CS0. Connect M16C’s CS3, CS2, and CS1 with address
inputs A21, A20, and A19 respectively. Connect M16C’s output A19 with address input A18. Figure 1.8.7
shows the relationship between addresses of the 4-M byte ROM and those of M16C.
With no offsets effected,
banks switch from one 512-K
byte segment to another
512-K byte segment. Bank
selection bits need to be
changed in dealing with data
lying across the boundary
between banks every time a
bank switches to another.
Assigning 1 to the offset bit
brings about offsets covering
40000
accessed without changing
the bank selection bits. For
instance, accessing 80000
of bank 0 with offsets ef-
fected causes the output
bank number to turn to 1, and
AD19 is inverted to be out-
put; this results in accessing
40000
On the other hand, the
SRAM’s chip select assumes
that CS0=1 (not selected)
and CS2=0 (selected), so
connect CS0 with S2 and
CS2 with S1. If the SRAM
doesn’t have a bipolar chip
select input terminal, decode
_______
CS0 and CS2 externally.
_______
_______
Tentative Specifications REV.A
_______
_______
16
S
16
16
16
16
pecifications in this manual are tentative and subject to change.
), and CS1 (28000
. Assigning 1 to the offset bit provides the means to set offsets covering 40000
, the bank number set by use of the bank selection bits are output from the output terminals CS3
of bank 1.
so that data can be
_______
_______
____
_______
16
through FFFFF
_______
16
16
- 3FFFF
Figure 1.8.6. An example of connecting the MCU with external
16
_______
, bank 7 (111
16
Note 1. If only one chip select terminal (S1 or S2) is present,
Note 2. M30623(80-pin package) is not provided with the
Note 3. The M16C/62T group is not guaranteed to operate
) is output depending on the address as in the past.
An example of connecting the MCU with
external memories in expansion mode 2
(M30622MC, Microprocessor mode)
A0 to A16
D0 to D7
16
_______
memories in expansion mode 2
through FFFFF
CS1
CS2
CS3
CS0
A17
A19
WR
RD
decoding by use of an external circuit is required.
output pin for the chip select signal.
in memory expansion and microprocessor modes.
26
2
) is output from CS3 - CS1 without regard to accessing
17
8
16
_______
. As for the area from 40000
2
_______
) is output from CS3 - CS1. As for the
SINGLE-CHIP 16-BIT CMOS MICROCOMPUTER
_______
DQ0 to
DQ7
OE
S2
D0 to D7
A0 to A16
A17
A18
A20
A21
CS
A0 to A16
W
A19
OE
S1
_______
16
_______
- 7FFF
Mitsubishi microcomputers
_______
M16C / 62T Group
16
_______
), CS2 (8000
16
_______
_______
.
16
through
16
_______
and
16
-