
Memory Space Expansion Features
22
Mitsubishi microcomputers
M16C / 62N Group
SINGLE-CHIP 16-BIT CMOS MICROCOMPUTER
(2) Expansion mode
In expansion mode, the data bank register (0000B16) goes effective. Figure 1.7.2 shows the data bank
register.
Figure 1.7.2. Data bank register
Data bank register
Symbol
Address
When reset
DBR
000B16
0016
Bit name
Description
Bit symbol
W
R
b7
b6
b5
b4
b3
b2
b1
b0
OFS
Offset bit
0: Not offset
1: Offset
BSR
Bank selection bits
0 0 0: Bank 0
0 0 1: Bank 1
0 1 0: Bank 2
0 1 1: Bank 3
1 0 0: Bank 4
1 0 1: Bank 5
1 1 0: Bank 6
1 1 1: Bank 7
Nothing is assigned.
In an attempt to write to these bits, write “0”. The value, if read, turns out to be “0”.
Nothing is assigned.
In an attempt to write to these bits, write “0”. The value, if read, turns out to be “0”.
b5 b4 b3
Microprocessor
mode
SFR area
Internal RAM area
External area
Internal area reserved
0000016
0040016
XXXXX16
YYYYY16
FFFFF16
D000016
0800016
Memory
expansion mode
SFR area
Internal RAM area
External area
Internal ROM area
Internal area reserved
CS3(16K bytes)
CS2(128K bytes)
CS1 (96K bytes)
2800016
4000016
0400016
Expansion mode (memory space = 4M bytes for PM15 = 1, PM14 = 1)
CS0
Addresses from 4000016 through BFFFF16
Bank 7 in fetching a program
A bank selected by use of the bank selection
bits in accessing data
Addresses from C000016 through FFFFF16
Bank 7 invariably
Bank number is output to CS3 to CS1
Memory expansion mode:
512K bytes x 7banks +
256K bytes
Microprocessor mode:
512K bytes x 8banks
Note 1: These memory maps show an instance in which PM13 is set to 0; but in the case of products in which the internal
RAM and the internal ROM are expanded to over 15 Kbytes and 192 Kbytes, respectively, they show an instance
in which PM13 is set to 1.
Note 2: The memory maps in single-chip mode are omitted.
Address YYYYY16
053FF16
Address XXXXX16
ROM size
02BFF16
10K bytes
20K bytes
RAM size
C000016
E000016
128K bytes
256K bytes
033FF16
12K bytes
Figure 1.7.3. Memory location and chip select area in expansion mode 2