Z8F042AHH020EG Zilog, Z8F042AHH020EG Datasheet - Page 100

• Manufacturer Part Number: Z8F042AHH020EG
• Description: IC ENCORE XP MCU FLASH 4K 20SSOP
• Manufacturer: Zilog
• Series: Encore!® XP®r

Specifications of Z8F042AHH020EG

• Core Processor: Z8
• Core Size: 8-Bit
• Speed: 20MHz
• Connectivity: IrDA, UART/USART
• Peripherals: Brown-out Detect/Reset, LED, LVD, POR, PWM, Temp Sensor, WDT
• Number Of I /o: 17
• Program Memory Size: 4KB (4K x 8)
• Program Memory Type: FLASH
• Eeprom Size: 128 x 8
• Ram Size: 1K x 8
• Voltage - Supply (vcc/vdd): 2.7 V ~ 3.6 V
• Data Converters: A/D 7x10b
• Oscillator Type: Internal
• Operating Temperature: -40°C ~ 105°C
• Package / Case: 20-SSOP
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant
• Other names: 269-4156; Z8F042AHH020EG

PS022517-0508
Table 49. Watchdog Timer Reload Upper Byte Register (WDTU)
BITS
FIELD
RESET
R/W
ADDR
R/W*—Read returns the current WDT count value. Write sets the desired Reload Value.
Watchdog Timer Reload Upper, High and Low Byte Registers
Caution:
STOP—Stop Mode Recovery Indicator
If this bit is set to 1, a Stop Mode Recovery occurred. If the STOP and WDT bits are both
set to 1, the Stop Mode Recovery occurred due to a WDT time-out. If the STOP bit is 1
and the WDT bit is 0, the Stop Mode Recovery was not caused by a WDT time-out. This bit
is reset by a POR or a WDT time-out that occurred while not in STOP mode. Reading this
register also resets this bit.
WDT—Watchdog Timer Time-Out Indicator
If this bit is set to 1, a WDT time-out occurred. A POR resets this pin. A Stop Mode
Recovery due a change in an input pin also resets this bit. Reading this register resets
this bit.
EXT—External Reset Indicator
If this bit is set to 1, a Reset initiated by the external RESET pin occurred. A POR or a
Stop Mode Recovery from a change in an input pin resets this bit. Reading this register
resets this bit.
Reserved
These bits are reserved and must be 0.
The Watchdog Timer Reload Upper, High and Low Byte (WDTU, WDTH, WDTL)
Registers
WDT, when a WDT instruction executes. The 24-bit reload value is {WDTU[7:0],
WDTH[7:0], WDTL[7:0]}. Writing to these registers sets the required Reload Value.
Reading from these registers returns the current WDT count value.
WDTU—WDT Reload Upper Byte
Most significant byte (MSB), Bits[23:16], of the 24-bit WDT reload value.
7
The 24-bit WDT Reload Value must not be set to a value less than
000004H
(Table 49
6
.
through
5
Table
51) form the 24-bit reload value that is loaded into the
4
WDTU
FF1H
R/W*
1
3
Z8 Encore! XP
2
Product Specification
1
®
F0822 Series
Watchdog Timer
0
87