PIC12F629-I/SN View Datasheet(PDF) - Microchip Technology

Part Name

Description

Manufacturer

PIC12F629-I/SN

8-Pin FLASH-Based 8-Bit CMOS Microcontrollers

Microchip Technology 

PIC12F629/675

9.3 RESET

The PIC12F629/675 differentiates between various

kinds of RESET:

a) Power-on Reset (POR)

b) WDT Reset during normal operation

c) WDT Reset during SLEEP

d) MCLR Reset during normal operation

e) MCLR Reset during SLEEP

f) Brown-out Detect (BOD)

Some registers are not affected in any RESET

condition; their status is unknown on POR and

unchanged in any other RESET. Most other registers

are reset to a “RESET state” on:

• Power-on Reset

• MCLR Reset

• WDT Reset

• WDT Reset during SLEEP

• Brown-out Detect (BOD) Reset

They are not affected by a WDT wake-up, since this is

viewed as the resumption of normal operation. TO and

PD bits are set or cleared differently in different RESET

situations as indicated in Table 9-4. These bits are

used in software to determine the nature of the RESET.

See Table 9-7 for a full description of RESET states of

all registers.

A simplified block diagram of the On-Chip Reset Circuit

is shown in Figure 9-4.

The MCLR Reset path has a noise filter to detect and

ignore small pulses. See Table 12-4 in Electrical

Specifications Section for pulse width specification.

FIGURE 9-4:

SIMPLIFIED BLOCK DIAGRAM OF ON-CHIP RESET CIRCUIT

External

Reset

MCLR/

VPP pin

VDD

WDT

Module

VDD Rise

Detect

SLEEP

WDT

Time-out

Reset

Power-on Reset

Brown-out

Detect

BODEN

OSC1/

CLKIN

pin

OST/PWRT

OST

10-bit Ripple Counter

On-chip(1)

RC OSC

PWRT

10-bit Ripple Counter

S

Q

Chip_Reset

R

Q

Enable PWRT

Enable OST

Note 1: This is a separate oscillator from the INTOSC/EC oscillator.

See Table 9-3 for time-out situations.

 2003 Microchip Technology Inc.

DS41190C-page 55

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