M16C26 Datasheet, PDF (200/239 Pages) Renesas Technology Corp – 16-BIT CMOS SINGLE-CHIP MICROCOMPUTER M16C FAMILY / M16C/20 SERIES

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Preliminary Specifications Rev. 0.9
Specifications in this manual are tentative and subject to change.
CPU Rewrite Mode (Flash Memory Version)
M16C/26 Group
SINGLE-CHIP 16-BIT CMOS MICROCOMPUTER
Program in ROM
Start
Transfer the program to be executed in the low
power dissipation mode, to the internal RAM.
Jump to transferred control program in RAM
(Subsequent operations are executed by control
program in this RAM)
*1
Program in RAM
*1
Set CPU rewrite mode select bit to 1
(by writing 0 and then 1 in succession)
Set flash memory reset bit to 1
(by writing 0 and then 1 in succession)(Note 1)
Switch the count source of BCLK.
XIN stop. (Note 2)
Process of low power dissipation mode
XIN oscillating Wait until the XIN has stabilized
Switch the count source of BCLK (Note 2)
Set flash memory reset bit to 0
Set CPU rewrite mode select bit to 0
Wait time until the internal circuit stabilizes (10 µs)
(Note 3)
End
Note 1: For flash memory reset bit to be set to 1 , the user needs to write a 0 and then a 1 to it in succession.
When it is not this procedure, it is not enacted in 1 . This is necessary to ensure that no interrupt or DMA
transfer will be executed during the interval.
Note 2: Before the count source for BCLK can be changed from XIN to XCIN or vice versa, the clock to which
the count source is going to be switched must be oscillating stably.
Note 3: Make a waiting time for 10 µs by software.
In this waiting time, do not access flash memory.
Figure 1.20.2c. Shifting to the low power dissipation mode flowchart
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