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Mitsubishi microcomputers
M16C / 62T Group
SINGLE-CHIP 16-BIT CMOS MICROCOMPUTER
Memory Space Expansion Functions
Memory Space Expansion Features
Here follows the description of the memory space expansion function.
With the processor running in memory expansion mode or in microprocessor mode, the memory space
expansion features provide the means of expanding the accessible space. The memory space expansion
features run in one of the three modes given below.
(1) Normal mode (no expansion)
(2) Memory space expansion mode 1 (to be referred as expansion mode 1)
(3) Memory space expansion mode 2 (to be referred as expansion mode 2)
Use bits 5 and 4 (PM15, PM14) of processor mode register 1 to select a desired mode. The external
memory area the chip select signal indicates is different in each mode so that the accessible memory space
varies. Table 1.8.1 shows how to set individual modes and corresponding accessible memory spaces. For
external memory area the chip select signal indicates, see Table 1.12.1 on page 33.
But M30623 (80-pin package) is not provided with the output pin for the chip select signal. And, the M16C/62T group
is not guaranteed to operate in memory expansion and microprocessor modes.
Table 1.8.1. The way of setting memory space expansion modes and corresponding memory spaces
Expansion mode
How to set PM15 and PM14
Accessible memory space
Normal mode (no expansion)
0, 0
Up to 1M byte
Expansion mode 1
1, 0
Up to 1.2M bytes
Expansion mode 2
1, 1
Up to 4M bytes
Here follows the description of individual modes.
(1) Normal mode (a mode with memory not expanded)
‘Normal mode’ means a mode in which memory is not expanded.
Figure 1.8.1 shows the memory maps and the chip select areas in normal mode.
Figure 1.8.1. The memory maps and the chip select areas in normal mode
Microprocessor mode
SFR area
Internal RAMarea
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 (32K bytes)
CS0
Memory expansion mode: 640K bytes
Microprocessor mode: 832K bytes
2800016
3000016
0400016
Normal mode (memory area = 1M bytes for PM15 = 0, PM14 = 0)
Type No.
XXXXX16 YYYYY16
M30623M4T-XXXGP
M30622M8T/M8V-XXXFP
M30623M8T/M8V-XXXGP
M30622MCT/MCV-XXXFP
M30623MCT/MCV-XXXGP
00FFF16
F800016
013FF16
F000016
017FF16
E000016
Note 1. M30623(80-pin package) is not provided with the output pins for chip select signals.
Note 2. The M16C/62T group is not guaranteed to operatein memory expansion and microprocessor modes.
Note 3. The memory maps in single-chip mode are omitted.