ZUSBOPTSC01ZAC datasheet(253/402 Pages) ZILOG

253 / 402 page

PS024604-1005

P R E L I M I N A R Y

Operation

Z8FMC16100 Series Flash MCU

Product Specification

231

Oscillator Control

The Z8FMC16100 Series Flash MCU uses three possible clocking schemes, each user-

selectable:

• Trimmable Internal Precision Oscillator

• On-chip oscillator using off-chip crystal/resonator or external clock driver

• On-chip low precision Watch-Dog Timer oscillator

In addition, Z8FMC16100 Series Flash MCUs contain clock failure detection and recov-

ery circuitry, allowing continued operation despite any potential failure of the primary

oscillator.

The on-chip system clock frequency can be reduced via a clock divider allowing reduced

dynamic power dissipation. Flash memory can be powered down during portions of the

clock period when running slower than 10MHz.

Operation

This section explains the logic used to select the system clock, divide down the system

clock, and handle oscillator failures. A description of the specific operation of each oscil-

lator is outlined elsewhere in this document. Refer to Watch-Dog Timer chapter on page

63, the On-Chip Oscillator chapter on page 237, and the Internal Precision Oscillator

chapter on page 239.

System Clock Selection

The oscillator control block selects from the available clocks. Table 129 details each clock

source and its usage.

ZUSBOPTSC01ZAC 数据表(PDF) 253 Page - Zilog, Inc.