PIC16F636T-I/SL(2005) View Datasheet(PDF) - Microchip Technology

Part Name

Description

Manufacturer

PIC16F636T-I/SL
(Rev.:2005)

8/14-Pin Flash-Based, 8-Bit CMOS Microcontrollers with nanoWatt Technology

Microchip Technology 

PIC12F635/PIC16F636/639

12.2 Reset

The PIC12F635/PIC16F636/639 differentiates between

various kinds of Reset:

a) Power-on Reset (POR)

b) Wake-up Reset (WUR)

c) WDT Reset during normal operation

d) WDT Reset during Sleep

e) MCLR Reset during normal operation

f) MCLR Reset during Sleep

g) 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

• MCLR Reset during Sleep

• WDT Reset

• Brown-out Detect

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 12-3. These bits are

used in software to determine the nature of the Reset.

See Table 12-4 for a full description of Reset states of

all registers.

A simplified block diagram of the On-Chip Reset Circuit

is shown in Figure 12-1.

The MCLR Reset path has a noise filter to detect and

ignore small pulses. See Section 15.0 “Electrical

Specifications” for pulse width specifications.

FIGURE 12-1:

SIMPLIFIED BLOCK DIAGRAM OF ON-CHIP RESET CIRCUIT

MCLR/VPP pin

VDD

External Reset

Sleep

WDT

Module

WDT

Time-out

Reset

VDD Rise

Detect

Power-on Reset

Brown-out(1)

Detect

BODEN <1>

BODEN<0>

SBODEN

OSC1/

CLKI pin

OST/PWRT

OST

10-bit Ripple Counter

PWRT

LFINTOSC

11-bit Ripple Counter

Sleep

WURE

Wake-up Interrupt

RA3 Change

S

Chip_Reset

R

Q

Note 1: Refer to the Configuration Word register (Register 12-1).

Enable PWRT

Enable OST

© 2005 Microchip Technology Inc.

Preliminary

DS41232B-page 113

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