Datasheet
2012 Microchip Technology Inc. Preliminary DS41652A-page 41
PIC16F527
8.0 SPECIAL FEATURES OF THE
CPU
What sets a microcontroller apart from other
processors are special circuits that deal with the needs
of real-time applications. The PIC16F527
microcontrollers have a host of such features intended
to maximize system reliability, minimize cost through
elimination of external components, provide power-
saving operating modes and offer code protection.
These features are:
• Oscillator Selection
• Reset:
- Power-on Reset (POR)
- Brown-out Reset (BOR)
- Device Reset Timer (DRT)
- Wake-up from Sleep on Pin Change
• Watchdog Timer (WDT)
• Sleep
• Code Protection
• ID Locations
• In-Circuit Serial Programming™
•Clock Out
The device has a Watchdog Timer, which can be shut
off only through Configuration bit WDTE. The
Watchdog Timer runs off of its own RC oscillator for
added reliability.
There is also a Device Reset Timer (DRT), intended to
keep the chip in Reset until the crystal oscillator is
stable. The DRT can be enabled with the DRTEN
Configuration bit. For the HS, XT or LP oscillator
options, the 18 ms (nominal) delay is always provided
by the Device Reset Timer and the DRTEN bit is
ignored. When using the EC clock, INTRC or EXTRC
oscillator options, there is a standard delay of 10 us on
power-up, which can be extended to 18 ms with the
use of the DRT timer. With the DRT timer on-chip,
most applications require no additional external Reset
circuitry.
The Sleep mode is designed to offer a very low current
Power-Down mode. The user can wake-up from Sleep
through a change on input pin or through a Watchdog
Timer time-out. Several oscillator options are also
made available to allow the part to fit the application,
including an internal 4/8 MHz oscillator. The EXTRC
oscillator option saves system cost while the LP crystal
option saves power. A set of Configuration bits are
used to select various options.
8.1 Configuration Bits
The PIC16F527 Configuration Words consist of 12 bits,
although some bits may be unimplemented and read as
‘1’. Configuration bits can be programmed to select
various device configurations. As an example, three bits
are for the selection of the oscillator type; one bit is the
Watchdog Timer enable bit, one bit is the MCLR
enable
bit and one bit is for code protection (Register 8-1).