Z8F0113HJ005EG Datasheet, PDF (37/245 Pages) Zilog, Inc. – High-Performance 8-Bit Microcontrollers

Z8 Encore! XP^® F0823 Series
Product Specification
22
During a System Reset or Stop Mode Recovery, the IPO requires 4 µs to start up. Then the
Z8 Encore! XP F0823 Series device is held in Reset for 66 cycles of the Internal Precision
Oscillator. If the crystal oscillator is enabled in the Flash option bits, this reset period is
increased to 5000 IPO cycles. When a reset occurs because of a low voltage condition or
Power-On Reset, this delay is measured from the time that the supply voltage first exceeds
the POR level. If the external pin reset remains asserted at the end of the reset period, the
device remains in reset until the pin is deasserted.
At the beginning of Reset, all GPIO pins are configured as inputs with pull-up resistor dis-
abled.
During Reset, the eZ8 CPU and on-chip peripherals are idle; however, the on-chip crystal
oscillator and Watchdog Timer oscillator continue to run.
Upon Reset, control registers within the Register File that have a defined Reset value are
loaded with their reset values. Other control registers (including the Stack Pointer, Regis-
ter Pointer, and Flags) and general-purpose RAM are undefined following Reset. The eZ8
CPU fetches the Reset vector at Program Memory addresses 0002H and 0003H and loads
that value into the Program Counter. Program execution begins at the Reset vector
address.
When the control registers are re-initialized by a system reset, the system clock after reset
is always the IPO. The software must reconfigure the oscillator control block, such that the
correct system clock source is enabled and selected.
PS024315-1011
PRELIMINARY
Reset Types