M16C6S_09 Datasheet, PDF (20/208 Pages) Renesas Technology Corp – SINGLE-CHIP 16-BIT CMOS MICROCOMPUTER

M16C/6S Group
Reset
Software Reset
When the PM03 bit in the PM0 register is set to “1” (microcomputer reset), the microcomputer has its pins,
CPU, and SFR initialized. Then the program is executed starting from the address indicated by the reset
vector.
Select the main clock for the CPU clock source, and set the PM03 bit to “1” with main clock oscillation
satisfactorily stable.
At software reset, some SFR’s are not initialized. Refer to “SFR”. Also, since the PM01 to PM00 bits in the
PM0 register are not initialized, the processor mode remains unchanged.
RESET
VCC
Recommended
operating
voltage
VCC
0V
RESET
0V
Equal to or less
than 0.2VCC
Equal to or less
than 0.2VCC
More than 20 cycles of XIN + td(P-R)
are needed.
Figure 1.5.1. Example Reset Circuit
Watchdog Timer Reset
Where the PM12 bit in the PM1 register is “1” (reset when watchdog timer underflows), the microcom-
puter initializes its pins, CPU and SFR if the watchdog timer underflows. Then the program is executed
starting from the address indicated by the reset vector.
At watchdog timer reset, some SFR’s are not initialized. Refer to “SFR”. Also, since the PM01 to PM00
bits in the PM0 register are not initialized, the processor mode remains unchanged.
Oscillation Stop Detection Reset
Where the CM27 bit in the CM2 register is “0” (reset at oscillation stop detection), the microcomputer
initializes its pins, CPU and SFR, coming to a halt if it detects main clock oscillation circuit stop. Refer to
the section “oscillation stop, re-oscillation detection function”.
At oscillation stop detection reset, some SFR’s are not initialized. Refer to the section “SFR”. Also, since
the PM01 to PM00 bits in the PM0 register are not initialized, the processor mode remains unchanged.
Rev.5.01 Dec 10, 2009 page 20 of 201
REJ03B0014-0501