PIC16F16-ESLASHSSQTP datasheet(67/136 Pages) MICROCHIP

67 / 136 page

DS41206B-page 65

PIC16F716

9.5

Power-up Timer (PWRT)

The Power-up Timer provides a fixed nominal time-out,

on power-up only, from the POR. The Power-up Timer

operates on an internal RC oscillator. The chip is kept

in Reset as long as the PWRT is active. The PWRT’s

time delay allows VDD to rise to an acceptable level.

The power-up timer enable Configuration bit, PWRTE,

is provided to enable/disable the PWRT.

The power-up time delay will vary from chip-to-chip due

to VDD, temperature and process variation. See AC

parameters for details.

9.6

Oscillator Start-up Timer (OST)

The Oscillator Start-up Timer (OST) provides a 1024

oscillator cycle (from OSC1 input) delay after the

PWRT delay is over. This ensures that the crystal

oscillator or resonator has started and stabilized. See

AC parameters for details.

The OST time-out is invoked only for XT, LP and HS

modes and only on Power-on Reset or wake-up from

Sleep.

9.7

Programmable Brown-Out Reset

(PBOR)

The PIC16F716 has on-chip Brown-out Reset circuitry.

A Configuration bit, BOREN, can disable (if clear/pro-

grammed) or enable (if set) the Brown-out Reset

circuitry.

The BORV Configuration bit selects the programmable

Brown-out Reset threshold voltage (VBOR). When

BORV is 1, VBOR IS 4.0V. When BORV is 0, VBOR is

2.5V

A Brown-out Reset occurs when VDD falls below VBOR

for a time greater than parameter TBOR (see Table 12-4).

A Brown-out Reset is not guaranteed to occur if VDD falls

below VBOR for less than parameter TBOR.

On any Reset (Power-on, Brown-out, Watchdog, etc.)

the chip will remain in Reset until VDD rises above

VBOR. The Power-up Timer will be invoked and will

keep the chip in Reset an additional 72 ms only if the

Power-up Timer enable bit in the Configuration register

is set to 0 (PWRTE = 0).

If the Power-up Timer is enabled and VDD drops below

VBOR while the Power-up Timer is running, the chip will

go back into a Brown-out Reset and the Power-up

Timer will be re-initialized. Once VDD rises above VBOR,

the Power-up Timer will execute a 72 ms Reset. See

Figure 9-6.

For operations where the desired brown-out voltage is

other than 4.0V or 2.5V, an external brown-out circuit

must be used. Figure 9-8, Figure 9-9 and Figure 9-10

show examples of external Brown-out Protection

circuits.

PIC16F16-E/SSQTP Datasheet(PDF) 67 Page - Microchip Technology

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