Z8F082ASJ020EG Datasheet, PDF (39/282 Pages) Zilog, Inc. – High-Performance 8-Bit Microcontrollers

Z8 Encore! XP^® F082A Series
Product Specification
22
Reset, Stop Mode Recovery and Low
Voltage Detection
The Reset Controller within the Z8 Encore! XP F082A Series controls Reset and Stop
Mode Recovery operation and provides indication of low supply voltage conditions. In
typical operation, the following events cause a Reset:
• Power-On Reset (POR)
• Voltage Brown-Out (VBO)
• Watchdog Timer time-out (when configured by the WDT_RES Flash option bit to ini-
tiate a reset)
• External RESET pin assertion (when the alternate RESET function is enabled by the
GPIO Register)
• On-chip debugger initiated Reset (OCDCTL[0] set to 1)
When the device is in STOP Mode, a Stop Mode Recovery is initiated by either of the fol-
lowing occurrences:
• Watchdog Timer time-out
• GPIO Port input pin transition on an enabled Stop Mode Recovery source
The low voltage detection circuitry on the device (available on the 8-pin product versions
only) performs the following functions:
• Generates the VBO reset when the supply voltage drops below a minimum safe level.
• Generates an interrupt when the supply voltage drops below a user-defined level (8-pin
devices only).
Reset Types
The Z8 Encore! XP F082A Series provides several different types of Reset operation. Stop
Mode Recovery is considered as a form of Reset. Table 8 lists the types of Reset and their
operating characteristics. The System Reset is longer if the external crystal oscillator is
enabled by the Flash option bits, allowing additional time for oscillator start-up.
PS022827-1212
P R E L I M I N A R Y Reset, Stop Mode Recovery and Low