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.
PS024604-1005
P R E L I M I N A R Y
Operation
ZILOG [ ZILOG, INC. ]
