PIC16F7X Datasheet, PDF (91/174 Pages) Microchip Technology – 28/40-Pin 8-Bit CMOS FLASH Microcontrollers

12.0 SPECIAL FEATURES OF THE
CPU
These devices have a host of features intended to max-
imize system reliability, minimize cost through elimina-
tion of external components, provide power saving
operating modes and offer code protection. These are:
• Oscillator Selection
• RESET
- Power-on Reset (POR)
- Power-up Timer (PWRT)
- Oscillator Start-up Timer (OST)
- Brown-out Reset (BOR)
• Interrupts
• Watchdog Timer (WDT)
• SLEEP
• Code Protection
• ID Locations
• In-Circuit Serial Programming
These devices have a Watchdog Timer, which can be
enabled or disabled, using a configuration bit. It runs off
its own RC oscillator for added reliability.
There are two timers that offer necessary delays on
power-up. One is the Oscillator Start-up Timer (OST),
intended to keep the chip in RESET until the crystal
oscillator is stable. The other is the Power-up Timer
(PWRT), which provides a fixed delay of 72 ms (nomi-
nal) on power-up only. It is designed to keep the part in
RESET while the power supply stabilizes, and is
enabled or disabled, using a configuration bit. With
these two timers on-chip, most applications need no
external RESET circuitry.
PIC16F7X
SLEEP mode is designed to offer a very low current
power-down mode. The user can wake-up from SLEEP
through external RESET, Watchdog Timer Wake-up, or
through an interrupt.
Several oscillator options are also made available to
allow the part to fit the application. The RC oscillator
option saves system cost while the LP crystal option
saves power. Configuration bits are used to select the
desired oscillator mode.
Additional information on special features is available
in the PICmicro™ Mid-Range Reference Manual
(DS33023).
12.1 Configuration Bits
The configuration bits can be programmed (read as '0'),
or left unprogrammed (read as '1'), to select various
device configurations. These bits are mapped in pro-
gram memory location 2007h.
The user will note that address 2007h is beyond the
user program memory space, which can be accessed
only during programming.
 2002 Microchip Technology Inc.
DS30325B-page 89