M16C28 Datasheet, PDF (53/423 Pages) Renesas Technology Corp – 16-BIT SINGLE-CHIP MICROCOMPUTER M16C FAMILY / M16C/Tiny SERIES

M16C/28 Group (M16C/28, M16C/28B)
5. Reset
RESET
VCC
Recommended
operating
VCC
voltage
0V
RESET
0V
Equal to or less
than 0.2VCC
Figure 5.1 Example Reset Circuit
Equal to or less
than 0.2VCC
More than td(ROC) + td(P-R)
5.2 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. The device will reset using internal on-chip oscillator as the CPU clock.
At software reset, some SFR’s are not initialized. Refer to 4. Special Function Register (SFR).
5.3 Watchdog Timer Reset
When the PM12 bit in the PM1 register is “1” (reset when watchdog timer underflows), the microcomputer
initializes its pins, CPU and SFR if the watchdog timer underflows. The device will reset using internal on-
chip oscillator as the CPU clock. 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 4. Special Function Register (SFR).
5.4 Oscillation Stop Detection Reset
When the CM20 bit in the CM2 register is set to “1” (oscillation stop, re-oscillation detection function en-
abled) and 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 7.8 oscillation stop, re-oscillation detection function.
At oscillation stop detection reset, some SFR’s are not initialized. Refer to the section 4. Special Function
Register (SFR).
Rev. 2.00 Jan. 31, 2007 ^{page 33} of 385
REJ09B0047-0200