PIC16C774 Microchip Technology Inc., PIC16C774 Datasheet - Page 131

• Manufacturer Part Number: PIC16C774
• Description: 28/40-pin, 8-bit Cmos Microcontrollers W/ 12-bit A/d
• Manufacturer: Microchip Technology Inc.

12.3
The PIC16C77X devices have several different resets.
These resets are grouped into two classifications;
power-up and non-power-up. The power-up type resets
are the power-on and brown-out resets which assume
the device V
for the device’s configuration. The non-power up type
resets assume normal operating limits were main-
tained before/during and after the reset.
• Power-on Reset (POR)
• Brown-out Reset (BOR)
• MCLR reset during normal operation
• MCLR reset during SLEEP
• WDT Reset (during normal operation)
FIGURE 12-5: SIMPLIFIED BLOCK DIAGRAM OF ON-CHIP RESET CIRCUIT
1999 Microchip Technology Inc.
MCLR
OSC1
Note 1:
V
DD
Reset
On-chip
RC OSC
This is a separate oscillator from the RC oscillator of the CLKIN pin.
OST/PWRT
DD
was below its normal operating range
Brown-out
V
(1)
Module
detect
WDT
DD
Reset
rise
OST
PWRT
10-bit Ripple counter
WDT
Reset
10-bit Ripple counter
Time-out
BODEN
Power-on Reset
External
Reset
SLEEP
Advance Information
Enable PWRT
Enable OST
Some registers are not affected in any reset condition.
Their status is unknown on a power-up reset and
unchanged in any other reset. Most other registers are
placed into an initialized state upon reset, however they
are not affected by a WDT reset during sleep because
this is considered a WDT Wakeup, which is viewed as
the resumption of normal operation.
Several status bits have been provided to indicate
which reset occurred (see
for a full description of reset states of all registers.
A simplified block diagram of the on-chip reset circuit is
shown in
These devices have a MCLR 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.
Figure
12-5.
PIC16C77X
Table
S
R
12-4). See
DS30275A-page 131
Q
Chip_Reset
Table 12-6