R8C13 datasheet(28/224 Pages) RENESAS

28 / 224 page

Rev.1.20

Jan 27, 2006

page 17 of 205

REJ09B0111-0120

R8C/13 Group

This is the reset generated by the voltage detection circuit which is built-in to the microcomputer. The

voltage detection circuit monitors the input voltage at Vcc input pin. The microcomputer is reset when

the voltage at the VCC input pin drops below Vdet if all of the following conditions hold true.

• The VC27 bit in the VCR2 register is set to “1” (voltage detection circuit enabled)

• The D40 bit in the D4INT register is set to “1” (voltage detection interrupt enabled)

• The D46 bit in the D4INT register is set to “1” (hardware reset 2 when going through Vdet)

When using a digital filter (D41 bit in the D4INT register is set to “1”), set the CM14 bit in the CM1

Conversely, when the input voltage at the VCC pin rises to Vdet or more, the pins, CPU, and SFR are

initialized and counting the low-speed on-chip oscillator starts. When counting the low-speed on-chip

oscillator clock 32 times, the internal reset is exited and the program is executed beginning with the

address indicated by the reset vector. The initialized pins and registers and the status thereof are the

same as in hardware reset 1. Refer to Section 5.4 “Voltage Detection Circuit.”

5.1.2 Hardware Reset 2

5.1 Hardware Reset

R8C13 Datasheet(PDF) 28 Page - Renesas Technology Corp