PIC16CR54C
The SLEEP mode is designed to offer a very low
current power-down mode. The user can wake up from
SLEEP through external reset or through a Watchdog
Timer time-out. 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.
7.0
SPECIAL FEATURES OF THE
CPU
What sets
a
microcontroller apart from other
processors are special circuits that deal with the
needs of real-time applications. The PIC16C5X family
of microcontrollers has
intended to maximize system reliability, minimize cost
through elimination of external components, provide
power saving operating modes and offer code
protection. These features are:
a host of such features
7.1
Configuration Bits
Configuration bits can be programmed to select
various device configurations. Two bits are for the
selection of the oscillator type and one bit is the
Watchdog Timer enable bit. Nine bits are code
protection bits (Figure 7-1 and Figure 7-2) for the
PIC16CR54C devices.
• Oscillator selection
• Reset
• Power-On Reset (POR)
• Device Reset Timer (DRT)
• Watchdog Timer (WDT)
• SLEEP
ROM devices have the oscillator configuration
programmed at the factory and these parts are tested
accordingly (see "Product Identification System"
diagrams in the back of this data sheet).
• Code protection
The PIC16CR54C Family has a Watchdog Timer
which can be shut off only through configuration bit
WDTE. It runs off of its own RC oscillator for added
reliability. There is an 18 ms delay provided by the
Device Reset Timer (DRT), intended to keep the chip
in reset until the crystal oscillator is stable. With this
timer on-chip, most applications need no external
reset circuitry.
FIGURE 7-1: CONFIGURATION WORD FOR PIC16CR54C
CP
CP
10
CP
9
CP
8
CP
7
CP
6
CP
5
CP
4
CP
3
WDTE FOSC1 FOSC0
bit0
Register: CONFIG
(1)
Address
:
0FFFh
bit11
2
1
bit 11-3: CP: Code protection bits
1 = Code protection off
0 = Code protection on
bit 2:
WDTE: Watchdog timer enable bit
1 = WDT enabled
0 = WDT disabled
bit 1-0: FOSC1:FOSC0: Oscillator selection bits
11 = RC oscillator
10 = HS oscillator
01 = XT oscillator
00 = LP oscillator
Note 1: Refer to the PIC16C5X Programming Specification (Literature number DS30190) to determine how to
access the configuration word.
1998 Microchip Technology Inc.
Preliminary
DS40191A-page 25
MICROCHIP [ MICROCHIP ]
