ST62T55C datasheet(21/86 Pages) STMICROELECTRONICS

No de pièce	ST62T55C

Description	8-BIT OTP/EPROM MCUs WITH A/D CONVERTER, SAFE RESET, AUTO-RELOAD TIMER, EEPROM AND SPI

PDF	86 Pages

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Fabricant	STMICROELECTRONICS [STMicroelectronics]

Site Internet	http://www.st.com

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ST62T55C ST62T65C/E65C

CLOCK SYSTEM (Cont’d)

Oscillator Control Registers

Address: DCh

—

Write only

Reset State: 00h

Bit 7-4. These bits are not used.

Bit 3. Reserved. Cleared at Reset. Must be kept

cleared.

Bit 2. Reserved. Must be kept low.

RS1-RS0. These bits select the division ratio of

the Oscillator Divider in order to generate the inter-

nal frequency. The following selctions are availa-

ble:

Note: Care is required when handling the OSCR

son, it is not allowed to change the OSCR contents

while executing interrupt service routine, as the

service routine cannot save and then restore its

previous content. If it is impossible to avoid the

writing of this register in interrupt service routine,

an image of this register must be saved in a RAM

location, and each time the program writes to

OSCR it must write also to the image register. The

image register must be written first, so if an inter-

rupt occurs between the two instructions the

OSCR is not affected.

---

OSCR

RS1

RS0

RS1

RS0

Division Ratio

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