PIC16F676 Microchip Technology Inc., PIC16F676 Datasheet - Page 59

• Manufacturer Part Number: PIC16F676
• Description: 14-pin, Flash-based 8-bit Cmos Microcontroller
• Manufacturer: Microchip Technology Inc.

9.3
The PIC16F630/676 differentiates between various
kinds of RESET:
a)
b)
c)
d)
e)
f)
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
• WDT Reset
• WDT Reset during SLEEP
• Brown-out Detect (BOD)
FIGURE 9-4:
© 2007 Microchip Technology Inc.
V
MCLR/
OSC1/
CLKIN
Note
PP
V
pin
Power-on Reset (POR)
WDT Reset during normal operation
WDT Reset during SLEEP
MCLR Reset during normal operation
MCLR Reset during SLEEP
Brown-out Detect (BOD)
DD
pin
RESET
1:
On-chip
RC OSC
OST/PWRT
This is a separate oscillator from the INTOSC/EC oscillator.
Brown-out
V
Module
Detect
DD
Detect
(1)
WDT
Rise
OST
PWRT
SIMPLIFIED BLOCK DIAGRAM OF ON-CHIP RESET CIRCUIT
10-bit Ripple Counter
Reset
10-bit Ripple Counter
WDT
Time-out
BODEN
Power-on Reset
External
Reset
SLEEP
Enable PWRT
Enable OST
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 9-4. These bits are
used in software to determine the nature of the RESET.
See Table 9-7 for a full description of RESET states of
all registers.
A simplified block diagram of the On-Chip Reset Circuit
is shown in Figure 9-4.
The MCLR Reset path has a noise filter to detect and
ignore small pulses. See Table 12-4 in Electrical
Specifications Section for pulse width specification.
See Table 9-3 for time-out situations.
PIC16F630/676
S
R
DS40039E-page 57
Q
Q
Chip_Reset