z8f083a ZiLOG Semiconductor, z8f083a Datasheet - Page 160

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

Table 95. Oscillator Control Register (OSCCTL)
Oscillator Control Register Definitions
BITS
FIELD
RESET
R/W
ADDR
PS026308-1207
Caution:
Oscillator Control Register
INTEN
R/W
7
1
The oscillator control register (OSCCTL) enables/disables the various oscillator circuits,
enables/disables the failure detection/recovery circuitry and selects the primary oscillator,
which becomes the system clock.
The oscillator control register must be unlocked before writing. Writing the two step
sequence
locked at successful completion of a register write to the OSCCTL.
displays the oscillator control clock switching flow. See
time of various oscillator circuits.
INTEN—Internal precision oscillator enable
1 = Internal precision oscillator is enabled
0 = Internal precision oscillator is disabled
XTLEN—Crystal oscillator enable; this setting overrides the GPIO register control for
PA0 and PA1
1 = Crystal oscillator is enabled
0 = Crystal oscillator is disabled
WDTEN—Watchdog Timer Oscillator enable
1 = Watchdog Timer Oscillator is enabled
0 = Watchdog Timer Oscillator is disabled
POFEN—Primary oscillator failure detection enable
1 = Failure detection and recovery of primary oscillator is enabled
0 = Failure detection and recovery of primary oscillator is disabled
It is possible to disable the clock failure detection circuitry as well as all functioning
clock sources. In this case, the Z8 Encore! F083A Series device ceases functioning and
is recovered only by power-on-reset.
XTLEN
E7H
R/W
6
0
followed by
WDTEN
R/W
5
1
18H
to the oscillator control register unlocks it. The register is
POFEN
R/W
4
0
F86H
WDFEN
R/W
3
0
Table 113
R/W
Z8 Encore!
2
0
Product Specification
on page 182 for waiting
Figure 21
SCKSEL
R/W
1
0
®
F083A Series
Oscillator Control
on page 149
R/W
0
0
148