R8CSLASH29 datasheet(48/471 Pages) RENESAS

48 / 471 page

R8C/28 Group, R8C/29 Group

5. Resets

Rev.2.10

Sep 26, 2008

Page 31 of 441

REJ09B0279-0210

5.6

Voltage Monitor 2 Reset

A reset is applied using the on-chip voltage detection 2 circuit. The voltage detection 2 circuit monitors the input

voltage to the VCC pin. The voltage to monitor is Vdet2.

When the input voltage to the VCC pin reaches the Vdet2 level or below, the pins, CPU, and SFR are reset and the

program beginning with the address indicated by the reset vector is executed. After reset, the low-speed on-chip

oscillator clock divided by 8 is automatically selected as the CPU clock.

The voltage monitor 2 does not reset some SFRs. Refer to 4. Special Function Registers (SFRs) for details.

The internal RAM is not reset. When the input voltage to the VCC pin reaches the Vdet2 level or below while

writing to the internal RAM is in progress, the contents of internal RAM are undefined.

Refer to 6. Voltage Detection Circuit for details of voltage monitor 2 reset.

5.7

Watchdog Timer Reset

When the PM12 bit in the PM1 register is set to 1 (reset when watchdog timer underflows), the MCU resets its pins,

CPU, and SFR if the watchdog timer underflows. Then the program beginning with the address indicated by the

reset vector is executed. After reset, the low-speed on-chip oscillator clock divided by 8 is automatically selected as

the CPU clock.

The watchdog timer reset does not reset some SFRs. Refer to 4. Special Function Registers (SFRs) for details.

The internal RAM is not reset. When the watchdog timer underflows, the contents of internal RAM are undefined.

Refer to 13. Watchdog Timer for details of the watchdog timer.

5.8

Software Reset

When the PM03 bit in the PM0 register is set to 1 (MCU reset), the MCU resets its pins, CPU, and SFR. The

program beginning with the address indicated by the reset vector is executed. After reset, the low-speed on-chip

oscillator clock divided by 8 is automatically selected for the CPU clock.

The software reset does not reset some SFRs. Refer to 4. Special Function Registers (SFRs) for details.

The internal RAM is not reset.

R8C/29 Datasheet(PDF) 48 Page - Renesas Technology Corp