Z8F042ASJ020EG2156 Datasheet, PDF (174/280 Pages) Zilog, Inc. – High-Performance 8-Bit Microcontrollers

Z8 Encore! XP^® F082A Series
Product Specification
159
Flash Option Bits
Programmable Flash option bits allow user configuration of certain aspects of Z8 Encore!
XP F082A Series operation. The feature configuration data is stored in Flash program
memory and loaded into holding registers during Reset. The features available for control
through the Flash option bits include:
• Watchdog Timer time-out response selection–interrupt or system reset
• Watchdog Timer always on (enabled at Reset)
• The ability to prevent unwanted read access to user code in Program Memory
• The ability to prevent accidental programming and erasure of all or a portion of the user
code in Program Memory
• Voltage Brown-Out configuration-always enabled or disabled during Stop Mode to re-
duce Stop Mode power consumption
• Oscillator mode selection-for high, medium and low power crystal oscillators, or exter-
nal RC oscillator
• Factory trimming information for the internal precision oscillator and low voltage de-
tection
• Factory calibration values for ADC, temperature sensor and Watchdog Timer compen-
sation
• Factory serialization and randomized lot identifier (optional)
Operation
This section describes the type and configuration of the programmable Flash option bits.
Option Bit Configuration By Reset
Each time the Flash option bits are programmed or erased, the device must be Reset for
the change to take effect. During any reset operation (System Reset, Power-On Reset, or
Stop Mode Recovery), the Flash option bits are automatically read from Flash program
memory and written to the Option Configuration registers. The Option Configuration reg-
isters control the operation of the devices within the Z8 Encore! XP F082A Series. Option
bit control is established before the device exits Reset and the eZ8 CPU begins code exe-
cution. The Option Configuration registers are not part of the Register File and are not
accessible for read or write access.
PS022828-0413
PRELIMINARY
Flash Option Bits