PIC16C716T-04I/SO View Datasheet(PDF) - Microchip Technology

Part Name

Description

Manufacturer

PIC16C716T-04I/SO

8-Bit CMOS Microcontrollers with A/D Converter and Capture/Compare/PWM

Microchip Technology 

PIC16C712/716

9.2.3 RC OSCILLATOR

For timing insensitive applications, the “RC” device

option offers additional cost savings. The RC oscillator

frequency is a function of the supply voltage, the resis-

tor (REXT) and capacitor (CEXT) values and the operat-

ing temperature. In addition to this, the oscillator

frequency will vary from unit to unit due to normal pro-

cess parameter variation. Furthermore, the difference

in lead frame capacitance between package types will

also affect the oscillation frequency, especially for low

CEXT values. The user also needs to take into account

variation due to tolerance of external R and C compo-

nents used. Figure 9-4 shows how the R/C combina-

tion is connected to the PIC16CXXX.

FIGURE 9-4: RC OSCILLATOR MODE

VDD

Rext

OSC1

Internal

clock

Cext

VSS

PIC16C7XX

OSC2/CLKOUT

Fosc/4

Recommended values: 3 kΩ ≤ Rext ≤ 100 kΩ

Cext > 20pF

9.3 Reset

The PIC16CXXX differentiates between various kinds

of reset:

• Power-on Reset (POR)

• MCLR reset during normal operation

• MCLR reset during SLEEP

• WDT Reset (during normal operation)

• WDT Wake-up (during SLEEP)

• Brown-out Reset (BOR)

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 (POR), on the MCLR and

WDT Reset, on MCLR reset during SLEEP and

Brown-out Reset (BOR). They are not affected by a

WDT Wake-up, which is viewed as the resumption of

normal operation. The TO and PD bits are set or

cleared differently in different reset situations as indi-

cated in Table 9-4. These bits are used in software to

determine the nature of the reset. See Table 9-6 for a

full description of reset states of all registers.

A simplified block diagram of the on-chip reset circuit is

shown in Figure 9-6.

The PICmicro microcontrollers have a MCLR noise fil-

ter in the MCLR reset path. The filter will detect and

ignore small pulses.

It should be noted that a WDT Reset does not drive

MCLR pin low.

DS41106A-page 54

Preliminary

© 1999 Microchip Technology Inc.

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