PIC16F636T-I/SL(2005) View Datasheet(PDF) - Microchip Technology

Part Name

Description

Manufacturer

PIC16F636T-I/SL
(Rev.:2005)

8/14-Pin Flash-Based, 8-Bit CMOS Microcontrollers with nanoWatt Technology

Microchip Technology 

PIC12F635/PIC16F636/639

3.4.2.1 OSCTUNE Register

The HFINTOSC is factory calibrated but can be

adjusted in software by writing to the OSCTUNE

register (Register 3-1).

The OSCTUNE register has a tuning range of

approximately ±12%. The default value of the

OSCTUNE register is ‘0’. The value is a 5-bit two’s

complement number. Due to process variation, the

monotonicity and frequency step cannot be specified.

When the OSCTUNE register is modified, the

HFINTOSC frequency will begin shifting to the new

frequency. The HFINTOSC clock will stabilize within

1 ms. Code execution continues during this shift. There

is no indication that the shift has occurred.

OSCTUNE does not affect the LFINTOSC frequency.

Operation of features that depend on the LFINTOSC

clock source frequency, such as the Power-up Timer

(PWRT), Watchdog Timer (WDT), Fail-Safe Clock

Monitor (FSCM) and peripherals, are not affected by

the change in frequency.

REGISTER 3-1:

bit 7-5

bit 4-0

OSCTUNE – OSCILLATOR TUNING REGISTER (ADDRESS: 90h)

U-0

U-0

U-0

R/W-0 R/W-0 R/W-0 R/W-0

—

—

—

TUN4

TUN3

TUN2

TUN1

bit 7

Unimplemented: Read as ‘0’

TUN<4:0>: Frequency Tuning bits

01111 = Maximum frequency

01110 =

•

•

•

00001 =

00000 = Oscillator module is running at the calibrated frequency.

11111 =

•

•

•

10000 = Minimum frequency

R/W-0

TUN0

bit 0

Legend:

R = Readable bit

- n = Value at POR

W = Writable bit

‘1’ = Bit is set

U = Unimplemented bit, read as ‘0’

‘0’ = Bit is cleared x = Bit is unknown

© 2005 Microchip Technology Inc.

Preliminary

DS41232B-page 33

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