PIC16F72 Datasheet, PDF (65/136 Pages) Microchip Technology – 28-Pin, 8-Bit CMOS FLASH MCU with A/D Converter

PIC16F72
FIGURE 11-4:
SIMPLIFIED BLOCK DIAGRAM OF ON-CHIP RESET CIRCUIT
External
RESET
MCLR
VDD
WDT
Module
VDD Rise
Detect
SLEEP
WDT
Time-out
Reset
Power-on Reset
Brown-out
Reset
BOREN
S
OST/PWRT
OST
10-bit Ripple Counter
R
OSC1
(1)
On-chip
RC OSC
PWRT
10-bit Ripple Counter
Chip_Reset
Q
Note 1: This is a separate oscillator from the RC oscillator of the CLKI pin.
Enable PWRT
Enable OST
11.4 MCLR
PIC16F72 device has a noise filter 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.
The behavior of the ESD protection on the MCLR pin
has been altered from previous devices of this family.
Voltages applied to the pin that exceed its specification
can result in both MCLR and excessive current beyond
the device specification during the ESD event. For this
reason, Microchip recommends that the MCLR pin no
longer be tied directly to VDD. The use of an
RC network, as shown in Figure 11-5, is suggested.
FIGURE 11-5:
VDD
RECOMMENDED MCLR
CIRCUIT
PIC16F72
R1
1 kΩ (or greater)
C1
0.1 µF
(optional, not critical)
MCLR
 2002 Microchip Technology Inc.
DS39597B-page 63