M16C Datasheet, PDF (214/262 Pages) Mitsubishi Electric Semiconductor – SINGLE-CHIP 16-BIT CMOS MICROCOMPUTER

Preliminary Specifications REV.B
Mitsubishi microcomputers
Specifications in this manual are tentative and subject to change.
M16C / 6N Group
SINGLE-CHIP 16-BIT CMOS MICROCOMPUTER
CPU Rewrite Mode
CPU Rewrite Mode
In CPU rewrite mode, the on-chip flash memory can be operated on (read, program or erase) under
control
of the Central Processing Unit (CPU).
In CPU rewrite mode, it is possible to write only in the user ROM area in Figure 22-3; in the boot ROM area
not possible. Make sure the program and block erase commands are issued only for the user ROM area
and each block area.
The control program for CPU rewrite mode can be stored in either user ROM- or boot ROM area. In CPU
rewrite mode, since the flash memory cannot be accessed for read by the CPU, use the rewrite control
program except in the internal flash memory.
Boot Mode
The control program for CPU rewrite mode must be rewritten into the user ROM- or boot ROM area in
parallel I/O mode beforehand. (If the control program is written into the boot ROM area, the standard
serial I/O mode becomes unusable.)
See Figure 23-3 for details about the boot ROM area.
Normal microcomputer mode is entered when the microcomputer is reset with pulling CNVss pin low. In
this case, the CPU starts operating, using the control program in the user ROM area.
When the microcomputer is reset by pulling the P55(EPM) pin low, the CNVss pin high, and the P50(CE)
pin high, the CPU start operating, using the control program in the boot ROM area. This mode is called
the "boot" mode. The control program in the boot ROM area can also be used to rewrite the user ROM
area.
Block Address
Block addresses refer to the maximum even address of each block. These addresses are used in the
block erase command, erase all unlock blocks command, lock bit program command and read lock
status command.
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