38K0 Datasheet, PDF (84/133 Pages) Mitsubishi Electric Semiconductor – SINGLE-CHIP 8-BIT CMOS MICROCOMPUTER

38K0 Group
Start
Single-chip mode or Boot mode (Note 1)
Set CPU mode register (Note 2)
Transfer CPU rewrite mode control program to
memory other than internal flash memory
Jump to control program transferred in memory
other than internal flash memory
(Subsequent operations are executed by control
program in this memory)
Set CPU rewrite mode select bit to “1” (by
writing “0” and then “1” in succession)
Check CPU rewrite mode entry flag
Using software command execute erase,
program, or other operation
Execute read array command or reset flash
memory by setting flash memory reset bit (by
writing “1” and then “0” in succession) (Note 3)
Write “0” to CPU rewrite mode select bit
End
Notes 1: When starting the MCU in the single-chip mode or memory expansion mode, supply
4.5 V to 5.25 V to the CNVss pin until checking the CPU rewrite mode entry flag.
2: Set the system clock division ration selection bits of CPU mode register (bits 6 and
7 at address 003B16).
3: Before exiting the CPU rewrite mode after completing erase or program operation,
always be sure to execute the read array command or reset the flash memory.
Fig. 118 CPU rewrite mode set/release flowchart
Rev.3.00 Oct 05, 2006 page 84 of 129
REJ03B0192-0300