P12C508 datasheet(25/84 Pages) MICROCHIP

25 / 84 page

Advance Information

DS40139A-page 25

PIC12C5XX

7.0

SPECIAL FEATURES OF THE

CPU

What

sets

microcontroller

apart

from

other

processors are special circuits to deal with the needs

of real-time applications. The PIC12C5XX family of

microcontrollers has a host of such features intended

to maximize system reliability, minimize cost through

elimination of external components, provide power

saving operating modes and offer code protection.

These features are:

• Oscillator selection

• Reset

- Power-On Reset (POR)

- Device Reset Timer (DRT)

- Wake-up from SLEEP on pin change

• Watchdog Timer (WDT)

• SLEEP

• Code protection

• ID locations

• In-circuit Serial Programming

The PIC12C5XX 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. If using

XT or LP selectable oscillator options, there is always

an 18 ms delay provided by the Device Reset Timer

(DRT), intended to keep the chip in reset until the

crystal oscillator is stable. If using INTRC or EXTRC

there is an 18 ms delay only on VDD power-up. With

this timer 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 a change on input pins or

through a Watchdog Timer time-out. Several oscillator

options are also made available to allow the part to ﬁt

the application, including an internal 4 MHz oscillator.

The EXTRL RC oscillator option saves system cost

while the LP crystal option saves power. A set of

conﬁguration bits are used to select various options.

7.1

Conﬁguration Bits

The PIC12C5XX conﬁguration word consists of 5 bits.

Conﬁguration bits can be programmed to select

various device conﬁgurations. Two bits are for the

selection of the oscillator type, one bit is the Watchdog

Timer enable bit, and one bit is the MCLR enable bit.

One bit is the code protection bit (Figure 7-1).

OTP

devices

have

the

oscillator

conﬁguration

programmed at the factory and these parts are tested

accordingly (see “Product Identiﬁcation System” on

the inside back cover).

FIGURE 7-1:

CONFIGURATION WORD FOR PIC12C508 OR PIC12C509

—

MCLRE

WDTE FOSC1 FOSC0

CONFIG

Address(1):

FFFh

bit11

987654321

bit0

bit 11-5:

Unimplemented

bit 4:

MCLRE: MCLR enable bit.

1 = MCLR enabled

0 = MCLR disabled

bit 3:

CP: Code protection bit.

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 = EXTRC - external RC oscillator

10 = INTRC - internal RC oscillator

01 = XT oscillator

00 = LP oscillator

Note 1:

Refer to the PIC12C5XX Programming Speciﬁcations to determine how to access the

conﬁguration word. This register is not user addressable during device operation.

P12C508 датащи(PDF) 25 Page - Microchip Technology

P12C508 датащи(HTML) 25 Page - Microchip Technology

Html Pages

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84

датащи скачать

ссылки URL