M16C62_N Datasheet, PDF (527/621 Pages) Renesas Technology Corp – 16-BIT SINGLE-CHIP MICROCOMPUTER M16C FAMILY

External Buses
Mitsubishi microcomputers
M16C / 62 Group
SINGLE-CHIP 16-BIT CMOS MICROCOMPUTER
5.3 Memory Space Expansion Features
Here follows the description of the memory space expansion function.
(1) Normal Mode
1M byte memory space
(2) Memory space expansion mode1 1.2M byte memory space
(3) Memory space expansion mode2 4M byte memory space
Use bits 5 and 4(PM15,PM14) of processor mode register 1 to select a desired mode.Figure 5.3.1 shows
the processor mode register 1.
Processor mode register 1 (Note 1)
b7 b6 b5 b4 b3 b2 b1 b0
0
0
Symbol
PM1
Address
000516
When reset
00000XX02
Bit symbol
Bit name
Function
RW
Reserved bit
Must always be set to “0”
Nothing is assigned.
In an attempt to write to these bits, write “0”. The value, if read, turns
out to be indeterminate.
PM13
Internal reserved area
expansion bit (Note 2)
0: The same internal reserved
area as that of M16C/60 and
M16C/61 group
1: Expands the internal RAM area
and internal ROM area to 23 K
bytes and to 256K bytes
respectively. (Note 2)
PM14
PM15
Memory area
expansion bit (Note 3)
b5 b4
0 0 : Normal mode
(Do not expand)
0 1 : Inhibited
1 0 : Memory area expansion
mode 1
1 1 : Memory area expansion
mode 2
Reserved bit
Must always be set to “0”
PM17
Wait bit
0 : No wait state
1 : Wait state inserted
Note 1: Set bit 1 of the protect register (address 000A16) to “1” when writing new values to this register.
Note 2: Be sure to set this bit to 0 except products whose RAM size and ROM size exceed 15K bytes
and 192K bytes respectively.
In using M30624MG/FG, a product having a RAM of more than 15K bytes and a ROM of more
than 192K bytes, set this bit to 1 at the beginning of user program.
Specify D000016 or a subsequent address, which becomes an internal ROM area if PM13 is set
to “0” at the time reset is revoked, for the reset vector table of user program.
Note 3: With the processor running in memory expansion mode or in microprocessor mode, setting this
bit provides the means of expanding the external memory area. (Normal mode: up to 1M byte,
expansion mode 1: up to 1.2 M bytes, expansion mode 2: up to 4M bytes)
For details, see “Memory space expansion functions”.
Figure 5.3.1. Processor mode register 1
512