M16C Datasheet, PDF (217/262 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
Set the bit 2 of FMCR2 (address 03B6₁₆) in order to reduce power consumption.Although setting this bit
to "1" helps to reduce the device's power consumption, programs cannot be read from the internal flash
memory. Make sure the operation to saet this bit to "1" and other operations to be performed while this
bit remains "1" are executed in areas outside flash memory.
Start
Single-chip mode, memory expansion
mode, or boot mode
Set processor mode register (Note 1)
Transfer CPU rewrite mode control
program to internal RAM
Jump to transferred control program in RAM
(Subsequent operations are executed by control
program in this RAM)
(Boot mode only)
Set user ROM area select bit to 1
Set CPU rewrite mode select bit to 1 (by
writing 0 and then 1 in succession)
Using software command execute erase,
program, or other operation
(Set lock bit disable bit as required)
Execute read array command or reset flash
memory by setting flash memory reset bit (by
writing 1 and then 0 in succession) (Note 2)
Write 0 to CPU rewrite mode select bit
(Boot mode only)
Write 0 to user ROM area select bit (Note 3)
End
Note 1: Set bit 7 (internal ROM access wait bit) of the processor mode register 1 (address
000516) to 1 (1 wait state).
Note 2: Before exiting the CPU rewrite mode after completing erase or program operation,
always be sure to execute a read array command or reset the flash memory.
Note 3: 1 can be set. However, when this bit is 1, user ROM area is accessed.
Figure 23-3 CPU rewrite mode set/reset flowchart
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