HT85F2270 datasheet(63/226 Pages) HOLTEK

63 / 226 page

Rev. 1.00

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Standard 8051 8-Bit Flash MCU

HT85F2260/HT85F2270/HT85F2280

High Speed Oscillator Control Register – HSOCR

SFR Address: EFh

Bit

Name

—

HXTRDY HIRCRDY

—

HXTEN

HIRCEN

R/W

—

R/W

POR

—

Bit 7~6

Unimplemented, read as “0”

Bit 5

HXTRDY: HXT oscillator ready indication bit

0: Not ready

1: Ready

This is the external high frequency oscillator, HXT, ready indication bit which indicates

if the HXT oscillator is stable or not. This bit will be cleared to zero by hardware when

the device is powered on. After power on, if the HXT oscillator is selected, the bit will

change to a high level when the external high frequency oscillator is stable.

Bit 4

HIRCRDY: HIRC oscillator ready indication bit

0: Not ready

1: Ready

This is the internal high frequency oscillator, HIRC, ready indication bit which indicates

if the HIRC oscillator is stable or not. This bit will be cleared to zero by hardware when

the HIRC function is disabled. After power on, if the HIRC oscillator is enabled, the bit

will change to a high level when the internal high frequency oscillator is stable.

Bit 3~2

Unimplemented, read as “0”

Bit 1

HXTEN: HXT control bit

0: Disable

1: Enable

Bit 0

HIRCEN: HIRC control bit

0: Disable

1: Enable

After power on, this bit will be set high thus selecting the HIRC as the initial system

oscillator.

Low Speed Oscillator Control Register – LSOCR

SFR Address: EEh

Bit

Name

—

LSORDY

—

LSOSEL

—

R/W

—

R/W

—

POR

—

Bit 7~5

Unimplemented, read as “0”

Bit 4

LSORDY: Low speed oscillator ready indication flag

0: Not ready

1: Ready

This is the common ready flag for the two low speed oscillators, LIRC and LXT,

which indicates if the low speed oscillator is stable or not. During low speed oscillator

switching this bit will be automatically cleared to zero by the hardware.

Bit 3~2

Unimplemented, read as “0”

Bit 1

LSOSEL: Low frequency oscillator select bit

0: LIRC

1: LXT

Bit 0

Unimplemented, read as “0”

HT85F2270 Datasheet(PDF) 63 Page - Holtek Semiconductor Inc

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