PIC16F684_07 Datasheet, PDF (99/192 Pages) Microchip Technology – 14-Pin, Flash-Based 8-Bit CMOS Microcontrollers with nanoWatt Technology

12.0 SPECIAL FEATURES OF THE
CPU
The PIC16F684 has a host of features intended to
maximize system reliability, minimize cost through
elimination of external components, provide power
saving features and offer code protection.
These features are:
• Reset
- Power-on Reset (POR)
- Power-up Timer (PWRT)
- Oscillator Start-up Timer (OST)
- Brown-out Reset (BOR)
• Interrupts
• Watchdog Timer (WDT)
• Oscillator selection
• Sleep
• Code protection
• ID Locations
• In-Circuit Serial Programming
The PIC16F684 has 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 64 ms (nominal) on power-up only, designed to keep
the part in Reset while the power supply stabilizes.
There is also circuitry to reset the device if a brown-out
occurs, which can use the Power-up Timer to provide
at least a 64 ms Reset. With these three
functions-on-chip, most applications need no 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:
• External Reset
• Watchdog Timer Wake-up
• An interrupt
Several oscillator options are also made available to
allow the part to fit the application. The INTOSC option
saves system cost while the LP crystal option saves
power. A set of configuration bits are used to select
various options (see Register 12-1).
PIC16F684
12.1 Configuration Bits
The Configuration bits can be programmed (read as
‘0’), or left unprogrammed (read as ‘1’) to select various
device configurations as shown in Register 12-1.
These bits are mapped in program memory location
2007h.
Note:
Address 2007h is beyond the user program
memory space. It belongs to the special
configuration
memory
space
(2000h-3FFFh), which can be accessed
only during programming. See
“PIC12F6XX/16F6XX Memory Program-
ming Specification” (DS41204) for more
information.
© 2007 Microchip Technology Inc.
DS41202F-page 97