z8f0813 ZiLOG Semiconductor, z8f0813 Datasheet - Page 175

• Manufacturer Part Number: z8f0813
• Description: High-performance 8-bit Microcontrollers
• Manufacturer: ZiLOG Semiconductor

Oscillator Control
Operation
Table 101. Oscillator Configuration and Selection
PS024314-0308
Clock Source
Internal Precision
RC Oscillator
External Clock
Drive
Internal Watchdog
Timer Oscillator
System Clock Selection
Z8 Encore! XP
user-selectable:
•
•
•
In addition, Z8 Encore! XP F0823 Series devices contain clock failure detection and
recovery circuitry, allowing continued operation despite a failure of the primary oscillator.
This chapter discusses the logic used to select the system clock and handle primary
oscillator failures. A description of the specific operation of each oscillator is outlined
elsewhere in this document.
The oscillator control block selects from the available clocks.
source and its usage.
On-chip precision trimmed RC oscillator
External clock drive
On-chip low power Watchdog Timer oscillator
Characteristics
• 32.8 kHz or 5.53 MHz
• ± 4% accuracy when trimmed
• No external components required
• 0 to 20 MHz
• Accuracy dependent on external clock
• 10 kHz nominal
• ± 40% accuracy; no external
• Very Low power consumption
source
components required
®
F0823 Series devices uses three possible clocking schemes, each
Required Setup
• Unlock and write Oscillator Control
• Write GPIO registers to configure PB3
• Unlock and write OSCCTL to select
• Apply external clock signal to GPIO
• Enable WDT if not enabled and wait
• Unlock and write Oscillator Control
Register (OSCCTL) to enable and
select oscillator at either 5.53 MHz or
32.8 kHz
pin for external clock function
external system clock
until WDT Oscillator is operating.
Register (OSCCTL) to enable and
select oscillator
Z8 Encore! XP
Table 101
Product Specification
details each clock
®
Oscillator Control
F0823 Series
165