Z8F0830HH020SG Datasheet, PDF (41/257 Pages) Zilog, Inc. – High-Performance 8-Bit Microcontrollers

Z8 Encore!^® F0830 Series
Product Specification
23
Reset Sources
Table 10 lists the possible sources of a system reset.
Table 10. Reset Sources and Resulting Reset Type
Operating Mode
NORMAL or HALT
modes
STOP Mode
Reset Source
Special Conditions
Power-On Reset/Voltage Brown-Out Reset delay begins after supply voltage
exceeds POR level.
Watchdog Timer time-out when con- None.
figured for reset
RESET pin assertion
All reset pulses less than four system clocks
in width are ignored.
On-Chip Debugger initiated reset
(OCDCTL[0] set to 1)
System, except the On-Chip Debugger is
unaffected by the reset.
Power-On Reset/Voltage Brown-Out Reset delay begins after supply voltage
exceeds POR level.
RESET pin assertion
All reset pulses less than 12 ns are ignored.
DBG pin driven Low
None.
Power-On Reset
Each device in the Z8 Encore! F0830 Series contains an internal Power-On Reset circuit.
The POR circuit monitors the digital supply voltage and holds the device in the Reset state
until the digital supply voltage reaches a safe operating level. After the supply voltage
exceeds the POR voltage threshold (V_POR), the device is held in the Reset state until the
POR counter has timed out. If the crystal oscillator is enabled by the option bits, the time-
out is longer.
After the Z8 Encore! F0830 Series device exits the Power-On Reset state, the eZ8 CPU
fetches the reset vector. Following the Power-On Reset, the POR status bit in the Reset
Status (RSTSTAT) Register is set to 1.
Figure 6 displays the Power-On Reset operation. See the Electrical Characteristics chapter
on page 184 for the POR threshold voltage (V_POR).
PS025113-1212
Reset Sources