Z8F0431SJ020SG Zilog, Z8F0431SJ020SG Datasheet - Page 95

• Manufacturer Part Number: Z8F0431SJ020SG
• Description: IC ENCORE XP MCU FLASH 4K 28SOIC
• Manufacturer: Zilog
• Series: Encore!®r

Specifications of Z8F0431SJ020SG

• Core Processor: Z8
• Core Size: 8-Bit
• Speed: 20MHz
• Peripherals: Brown-out Detect/Reset, LED, POR, PWM, WDT
• Number Of I /o: 25
• Program Memory Size: 4KB (4K x 8)
• Program Memory Type: FLASH
• Ram Size: 256 x 8
• Voltage - Supply (vcc/vdd): 2.7 V ~ 3.6 V
• Oscillator Type: Internal
• Operating Temperature: 0°C ~ 70°C
• Package / Case: 28-SOIC (7.5mm Width)
• For Use With: 770-1002 - ISP 4PORT ZILOG Z8 ENCORE! MCU
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant
• Eeprom Size: -
• Data Converters: -
• Connectivity: -
• Other names: 269-4627-5

Watchdog Timer
Operation
Table 55. Watchdog Timer Approximate Time-Out Delays
PS025111-1207
WDT Reload Value
(Hex)
000004
The Watchdog Timer (WDT) protects from corrupted or unreliable software, power faults,
and other system-level problems, which may place the Z8 Encore!
into unsuitable operating states. The features of Watchdog Timer include:
•
•
•
The Watchdog Timer is a re-triggerable one-shot timer that resets or interrupts the Z8
Encore! F0830 Series devices when the WDT reaches its terminal count. The WDT uses a
dedicated on-chip RC oscillator as its clock source. The WDT operates only in two modes:
ON and OFF. Once enabled, it always counts and must be refreshed to prevent a time-out.
Perform an enable by executing the WDT instruction or by setting the WDT_AO Flash
option bit. The WDT_AO bit forces the WDT to operate immediately on reset, even if a
WDT instruction has not been executed.
The Watchdog Timer is a 24-bit reloadable downcounter that uses three 8-bit registers in
the eZ8 CPU register space to set the reload value. The nominal WDT time-out period is
calculated using the following equation:
where the WDT reload value is the 24-bit decimal value given by {WDTU[7:0],
WDTH[7:0], WDTL[7:0]} and the typical Watchdog Timer RC oscillator frequency is 10
KHz. The Watchdog Timer cannot be refreshed after it reaches
reload value must not be set to values below
about approximate time-out delays for the minimum and maximum WDT reload values.
WDT Time-out Period (ms)
On-chip RC oscillator
A selectable time-out response: reset or interrupt
24-bit programmable time-out value
WDT Reload Value
(Decimal)
4
Approximate Time-Out Delay
(with 10 kHz typical WDT oscillator frequency)
Typical
=
WDT Reload Value
------------------------------------------------- -
400 µs
000004H
10
.
Table 55
Z8 Encore!
000002H
Description
Minimum time-out delay
Product Specification
provides information
®
F0830 Series devices
®
. The WDT
F0830 Series
Watchdog Timer
85