z16f2811 ZiLOG Semiconductor, z16f2811 Datasheet - Page 341

• Manufacturer Part Number: z16f2811
• Description: High Performance Microcontrollers
• Manufacturer: ZiLOG Semiconductor

Table 179. Oscillator Configuration and Selection
Oscillator Control
Operation
PS022006-0207
Clock Source
Internal Precision
Oscillator
External Crystal/
Resonator/
External Clock
Drive
Internal
Watchdog Timer
Oscillator
System Clock Selection
The ZNEO Z16F Series uses three possible user-selectable clocking schemes:
•
•
•
In addition, ZNEO Z16F Series contain clock failure detection and recovery circuitry,
allowing continued operation despite a failure of the primary oscillator.
The on-chip system clock frequency is reduced through a clock divider allowing reduced
dynamic power dissipation. The FLASH is powered down during portions of the clock
period when running slower than 10 MHz.
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
oscillator is outlined elsewhere in this document. See
Internal Precision Oscillator
The oscillator control block selects from the available clocks.
details each clock source and its usage.
Characteristics
• 5.5 MHz
• High precision possible when
• No external components
• 0 to 20 MHz
• Very high accuracy (dependent
• Requires external components
• 10 kHz nominal
• Low accuracy
• No external components
• Low power consumption
Trimmable internal precision oscillator.
On-chip oscillator using off-chip crystal/resonator or external clock driver.
On-chip low precision Watchdog Timer oscillator.
required
on crystal/resonator or external
source)
required
trimmed
P R E L I M I N A R Y
on page 332, and
Required Setup
• This is the reset default.
• Configure Option Bits for correct external
• Unlock and write Oscillator Control Register
• Wait for required stabilization time
• Unlock and write Oscillator Control Register
• Unlock and write Oscillator Control Register
(OSCCTL) to select external oscillator
(OSCCTL) to enable and select Internal WDT
oscillator
oscillator mode
(OSCCTL) to enable external oscillator
On-Chip Oscillator
Watchdog Timer
Table 179
Product Specification
ZNEO
on page 323.
on page 235,
on page 327
Oscillator Control
™
Z16F Series
327