PIC16F636-I Datasheet, PDF (131/234 Pages) Microchip Technology – 8/14-Pin, Flash-Based 8-Bit CMOS Microcontrollers with nanoWatt Technology

PIC12F635/PIC16F636/639
12.0 SPECIAL FEATURES OF THE
CPU
The PIC12F635/PIC16F636/639 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)
- Wake-up Reset (WUR)
- 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 PIC12F635/PIC16F636/639 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 nominal 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).
12.1 Configuration Bits
The Configuration Word 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 Programming Specification”
(DS41204) for more information.
© 2007 Microchip Technology Inc.
DS41232D-page 129