PIC16C621A Microchip Technology Inc., PIC16C621A Datasheet - Page 47

• Manufacturer Part Number: PIC16C621A
• Description: Eprom-based 8-bit Cmos Microcontrollers
• Manufacturer: Microchip Technology Inc.

9.0
Special circuits to deal with the needs of real-time
applications are what sets a microcontroller apart from
other processors. The PIC16C62X family has a host of
such features intended to maximize system reliability,
minimize cost through elimination of external compo-
nents, provide power saving operating modes and offer
code protection.
These are:
1.
2.
3.
4.
5.
6.
7.
8.
 2003 Microchip Technology Inc.
OSC 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™
SPECIAL FEATURES OF THE
CPU
The PIC16C62X devices have a Watchdog Timer
which is controlled by configuration bits. 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 (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 pro-
vides at least a 72 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 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. A set of
configuration bits are used to select various options.
PIC16C62X
DS30235J-page 45