PIC16F753 Datasheet, PDF (163/238 Pages) Microchip Technology – 14/16-Pin, Flash-Based 8-Bit CMOS Microcontrollers

PIC16F753/HV753
19.2 Calibration Bits
The 8 MHz internal oscillator is factory calibrated.
These calibration values are stored in fuses located in
the Calibration Word (2008h). The Calibration Word is
not erased when using the specified bulk erase
sequence in the “PIC16F753/HV753 Flash Memory
Programming Specification” (DS41686) and thus, does
not require reprogramming.
19.3 Reset
The PIC16F753/HV753 device 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 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
• MCLR Reset
• MCLR Reset during Sleep
• WDT Reset
• Brown-out Reset (BOR)
WDT wake-up does not cause register Resets in the
same manner as a WDT Reset since wake-up 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 19-2. Software can use
these bits to determine the nature of the Reset. See
Table 19-4 for a full description of Reset states of all
registers.
A simplified block diagram of the On-Chip Reset Circuit
is shown in Figure 19-1.
The MCLR Reset path has a noise filter to detect and
ignore small pulses. See Section 22.0 “Electrical
Specifications” for pulse-width specifications.
FIGURE 19-1:
SIMPLIFIED BLOCK DIAGRAM OF ON-CHIP RESET CIRCUIT
External
Reset
MCLR/VPP pin
Sleep
WDT
Module
WDT
Time-out
Reset
VDD Rise
Detect
VDD
Power-on Reset
Brown-out⁽¹⁾
Reset
BOREN
S
On-Chip
RC OSC
PWRT
11-bit Ripple Counter
Chip_Reset
R
Q
Note 1: Refer to the Configuration Word register (Register 19-1).
Enable PWRT
 2013 Microchip Technology Inc.
Preliminary
DS40001709A-page 163