16F84 MICROCHIP [Microchip Technology], 16F84 Datasheet - Page 37

• Manufacturer Part Number: 16F84
• Description: 18-pin Flash/EEPROM 8-Bit Microcontrollers
• Manufacturer: MICROCHIP [Microchip Technology]

8.0
What sets a microcontroller apart from other
processors are special circuits to deal with the needs of
real time applications. The PIC16F8X has a host of
such features intended to maximize system reliability,
minimize
components, provide power saving operating modes
and offer code protection. These features are:
• OSC Selection
• Reset
• Interrupts
• Watchdog Timer (WDT)
• SLEEP
• Code protection
• ID locations
• In-circuit serial programming
The PIC16F8X has a Watchdog Timer which can be
shut off only through 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. This
design keeps the device in reset while the power supply
stabilizes. With these two timers on-chip, most
applications need no external reset circuitry.
SLEEP mode offers a very low current power-down
mode. The user can wake-up from SLEEP through
external reset, Watchdog Timer time-out or through an
interrupt. Several oscillator options are provided 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 the various options.
1998 Microchip Technology Inc.
- Power-on Reset (POR)
- Power-up Timer (PWRT)
- Oscillator Start-up Timer (OST)
SPECIAL FEATURES OF THE
CPU
cost
through
elimination
of
external
8.1
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
program memory location 2007h.
Address 2007h is beyond the user program memory
space and it belongs to the special test/configuration
memory space (2000h - 3FFFh). This space can only
be accessed during programming.
To find out how to program the PIC16C84, refer to
PIC16C84 EEPROM Memory Programming Specifica-
tion (DS30189).
Configuration Bits
PIC16F8X
DS30430C-page 37