M16CSLASH29 datasheet(60/499 Pages) RENESAS

60 / 499 page

5. Resets

page 36

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)

Figure 5.1 Example Reset Circuit

RESET

VCC

RESET

VCC

More than td(ROC) + td(P-R)

Equal to or less

than 0.2VCC

Equal to or less

than 0.2VCC

Recommended

operating

voltage

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