Z8 Encore! XP® F08xA Series
Product Specification
25
trol Register is set to 1. Table 10 lists the STOP Mode Recovery sources and resulting
actions. The text following provides more detailed information about each of the STOP
Mode Recovery sources.
Table 10. STOP Mode Recovery Sources and Resulting Action
Operating Mode
STOP Mode Recovery Source
Action
STOP mode
Watch-Dog Timer time-out
when configured for Reset
STOP Mode Recovery
Watch-Dog Timer time-out
when configured for interrupt
STOP Mode Recovery followed by
interrupt (if interrupts are enabled)
Data transition on any GPIO Port pin STOP Mode Recovery
enabled as a STOP Mode Recovery
source
Assertion of external RESET Pin
Debug Pin driven Low
System Reset
System Reset
STOP Mode Recovery Using Watch-Dog Timer Time-Out
If the Watch-Dog Timer times out during STOP mode, the device undergoes a STOP
Mode Recovery sequence. In the Watch-Dog Timer Control register, the WDT and STOP
bits are set to 1. If the Watch-Dog Timer is configured to generate an interrupt upon time-
out and the Z8 Encore! XP® F08xA Series device is configured to respond to interrupts,
the eZ8 CPU services the Watch-Dog Timer interrupt request following the normal STOP
Mode Recovery sequence.
STOP Mode Recovery Using a GPIO Port Pin Transition
Each of the GPIO Port pins may be configured as a STOP Mode Recovery input source.
On any GPIO pin enabled as a STOP Mode Recovery source, a change in the input pin
value (from High to Low or from Low to High) initiates STOP Mode Recovery. In the
Watch-Dog Timer Control register, the STOPbit is set to 1.
In STOP mode, the GPIO Port Input Data registers (PxIN) are disabled. The Port Input
Data registers record the Port transition only if the signal stays on the Port pin through
the end of the STOP Mode Recovery delay. As a result, short pulses on the Port pin can
initiate STOP Mode Recovery without being written to the Port Input Data register or
without initiating an interrupt (if enabled for that pin).
Caution:
PS024705-0405
P R E L I M I N A R Y
Reset and STOP Mode Recovery
ZILOG [ ZILOG, INC. ]
