z8f083a ZiLOG Semiconductor, z8f083a Datasheet - Page 161

• Manufacturer Part Number: z8f083a
• Description: High-performance 8-bit Microcontrollers
• Manufacturer: ZiLOG Semiconductor

PS026308-1207
OSCCTL register
1.5ms@20MHz
Set bit6 in
and wait
NO
NO
WDFEN—Watchdog Timer Oscillator failure detection enable
1 = Failure detection of Watchdog Timer Oscillator is enabled
0 = Failure detection of Watchdog Timer Oscillator is disabled
SCKSEL—System clock oscillator select
000 = Internal precision oscillator functions as system clock at 20 MHz
001 = Internal precision oscillator functions as system clock at 119 kHz
010 = Crystal oscillator or external RC oscillator functions as system clock
011 = Watchdog Timer Oscillator functions as system clock
100 = External clock signal on PB3 functions as system clock
101 = Reserved
110 = Reserved
111 = Reserved
to unlock OSCCTL
Write to OSCCTL
Write to OSCCTL
OSC is enabled?
Switch to OSC?
010 to bits [2:0]
register:
register:
register
Figure 21. Oscillator Control Clock Switching Flow Chart
E7
18
YES
YES
Set bit7 in OSCCTL
bandgap is closed)
register and wait
instruction(wait
25 us if IPO
one NOP
NO
NO
Write to OSCCTL register:
Write to OSCCTL register:
to unlock OSCCTL
Normal Running
IPO is enabled?
000 to bits [2:0]
Switch to IPO?
register
E7
18
YES
YES
Set bit5 in OSCCTL
register and wait
50us
NO
Z8 Encore!
NO
Write to OSCCTL register:
Write to OSCCTL register:
Product Specification
to unlock OSCCTL
Switch to WDT?
011 to bits [2:0]
WDT OSC is
enabled?
register
E7
18
YES
YES
®
F083A Series
Oscillator Control
149