Z8F0431SJ020SG Zilog, Z8F0431SJ020SG Datasheet - Page 98

• 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

Table 56. Watchdog Timer Control Register (WDTCTL)
Watchdog Timer Control Register Definitions
BITS
FIELD
RESET
R/W
ADDR
PS025111-1207
Caution:
Watchdog Timer Control Register
Watchdog Timer Reload Upper, High, and Low Byte Registers
W
X
7
occurs, the lock state machine resets and no further writes can occur unless the sequence is
restarted. The value in the Watchdog Timer reload registers is loaded into the counter
when the Watchdog Timer is first enabled and every time a WDT instruction is executed.
The Watchdog Timer control (WDTCTL) register is a write-only control register. Writing
the unlock sequence:
Watchdog Timer reload byte registers (WDTU, WDTH, and WDTL) to allow changes to
the time-out period. These Write operations to the WDTCTL register address have no
effect on the bits in the WDTCTL register. The locking mechanism prevents spurious
writes to the reload registers.
This register address is shared with the read-only reset status register.
WDTUNLK—Watchdog Timer unlock
The user software must write the correct unlocking sequence to this register before it is
allowed to modify the contents of the Watchdog Timer reload registers.
The Watchdog Timer reload upper, high and low byte (WDTU, WDTH, WDTL) registers
(Table 57
WDTH[7:0], WDTL[7:0]} that is loaded into the Watchdog Timer, when a WDT
instruction is executed. Writing to these registers sets the appropriate reload value.
Reading from these registers returns the current Watchdog Timer count value.
The 24-bit WDT reload value must not be set to a value less than
through
W
X
6
Table 59
55H
W
X
5
,
AAH
on page 89) form the 24-bit reload value{WDTU[7:0],
to the WDTCTL register address unlocks the three
W
X
4
WDTUNLK
FF0H
W
X
3
W
X
Z8 Encore!
2
Product Specification
W
X
1
®
000004H
F0830 Series
Watchdog Timer
.
W
X
0
88