M16C29 Datasheet, PDF (60/499 Pages) Renesas Technology Corp – RENESAS MCU M16C FAMILY / M16C/Tiny SERIES

M16C/29 Group
5. Resets
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
The MCU resets its pins, CPU, and SFRs when the PM03 bit in the PM0 register is set to 1 (reset) and the
MCU executes a program in an address indicated by the reset vector. Then the on-chip oscillator is se-
lected as the CPU clock.
The software reset does not reset some portions of the SFRs. Refer to 4. Special Function Registers
(SFRs) for details.
5.3 Watchdog Timer Reset
The MCU resets its pins, CPU, and SFRs when the PM12 bit in the PM1 register is set to 1 (watchdog timer
reset) and the watchdog timer underflows. The MCU executes a program in an address indicated by the
reset vector. Then the on-chip oscillator is selected as the CPU clock.
The watchdog timer reset does not reset some portions of the SFRs. Refer to 4. Special Function Regis-
ters (SFRs) for details.
5.4 Oscillation Stop Detection Reset
The MCU resets its pins, CPU, and SFRs and stops if the main clock stop is detected when the CM20 bit in
the CM2 register is set to 1 (oscillation stop, re-oscillation detection function enabled) and the CM27 bit in
the CM2 register is 0 (reset at oscillation stop detection). Refer to the section 7.8 oscillation stop, re-
oscillation detection function for details.
The oscillation stop detection reset does not reset some portions of the SFRs. Refer to 4. Special Func-
tion Registers (SFRs).
Rev. 1.12 Mar.30, 2007
REJ09B0101-0112
page 36 _{of 458}