Datasheet

© 2009 Microchip Technology Inc. DS41203E-page 109
PIC16F688
11.0 SPECIAL FEATURES OF THE
CPU
The PIC16F688 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 PIC16F688 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 11-1).