HT82R732 datasheet(21/74 Pages) HOLTEK

21 / 74 page

Oscillator

Various oscillator options offer the user a wide range of functions according to their application

requirements. The flexible features of the oscillator functions ensure that the best optimisation can be

achieved in terms of speed and power saving. Oscillator selections and operation are selected through

a combination of configuration options and registers.

System Oscillator Overview

In addition to being the source of the main system clock the oscillators also provide clock sources for

the Watchdog Timer and Time Base functions. An external oscillator requiring some external

components as well as two fully integrated internal oscillators, requiring no external components, are

provided to form a range of both fast and slow system oscillators.

Type

Name

Freq.

Pins

Internal High Speed RC

HIRC

4MHz

External Low Speed Crystal

LXT

32768Hz

XT1/XT2

Internal Low Speed RC

LIRC

12kHz

The oscillator is connected to the XT1/XT2 pins with TinyPower

TM design.

System Clock Configurations

There are three system oscillators, one high speed oscillator and two low speed oscillators. The high

speed oscillator is the internal RC oscillator -- HIRC. The two low speed oscillators are the external

32768Hz oscillator -- LXT and the internal 12kHz (VDD=5V) oscillator -- LIRC.

Internal RC Oscillator

- HIRC

The internal RC oscillator is a fully integrated system oscillator requiring no external components. The

internal RC oscillator has fixed frequency of 4MHz. Device trimming during the manufacturing

process and the inclusion of internal frequency compensation circuits are used to ensure that the

influence of the power supply voltage, temperature and process variations on the oscillation frequency

are minimised. As a result, at a power supply of either 3V or 5V and at a temperature of 25 degrees, the

fixed oscillation frequency of 4MHz will have a tolerance within 2%.

HT82R732

e-Banking 8-Bit OTP MCU

Rev. 1.00

October 31, 2013

4 M H z

H I R C

L I R C

L X T

3 2 k H z

1 2 k H z

f S Y S

W a t c h d o g

T i m e r

L C D

T i m e B a s e

¸ 4

HT82R732 数据表(PDF) 21 Page - Holtek Semiconductor Inc

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