PIC18C442-E/L Microchip Technology, PIC18C442-E/L Datasheet - Page 185

• Manufacturer Part Number: PIC18C442-E/L
• Description: IC MCU OTP 8KX16 A/D 44PLCC
• Manufacturer: Microchip Technology
• Series: PIC® 18Cr

Specifications of PIC18C442-E/L

• Core Processor: PIC
• Core Size: 8-Bit
• Speed: 40MHz
• Connectivity: I²C, SPI, UART/USART
• Peripherals: Brown-out Detect/Reset, LVD, POR, PWM, WDT
• Number Of I /o: 33
• Program Memory Size: 16KB (8K x 16)
• Program Memory Type: OTP
• Ram Size: 512 x 8
• Voltage - Supply (vcc/vdd): 4.2 V ~ 5.5 V
• Data Converters: A/D 8x10b
• Oscillator Type: External
• Operating Temperature: -40°C ~ 125°C
• Package / Case: 44-PLCC
• For Use With: DVA16XL441 - ADAPTER DEVICE ICE 44PLCC
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant
• Eeprom Size: -
• Other names: PIC18C442E/L

18.2
The Watchdog Timer is a free running, on-chip RC
oscillator, which does not require any external compo-
nents. This RC oscillator is separate from the RC oscil-
lator of the OSC1/CLKI pin. That means that the WDT
will run, even if the clock on the OSC1/CLKI and OSC2/
CLKO/RA6 pins of the device has been stopped, for
example, by execution of a SLEEP instruction.
During normal operation, a WDT time-out generates a
device RESET (Watchdog Timer Reset). If the device is
in SLEEP mode, a WDT time-out causes the device to
wake-up and continue with normal operation (Watch-
dog Timer Wake-up). The TO bit in the RCON register
will be cleared upon a WDT time-out.
The Watchdog Timer is enabled/disabled by a device
configuration bit. If the WDT is enabled, software exe-
cution may not disable this function. When the WDTEN
configuration bit is cleared, the SWDTEN bit enables/
disables the operation of the WDT.
REGISTER 18-7:
2000 Microchip Technology Inc.
Watchdog Timer (WDT)
bit 7-1
bit 0
WDTCON REGISTER
bit 7
Unimplemented: Read as ’0’
SWDTEN: Software Controlled Watchdog Timer Enable bit
1 = Watchdog Timer is on
0 = Watchdog Timer is turned off if the WDTEN configuration bit in the configuration
Legend:
R = Readable bit
U = Unimplemented bit, read as ‘0’
U-0
—
register = ’0’
U-0
—
U-0
—
U-0
The WDT time-out period values may be found in the
Electrical Specifications section under parameter #31.
Values for the WDT postscaler may be assigned using
the configuration bits.
18.2.1
Register 18-7 shows the WDTCON register. This is a
readable and writable register, which contains a control
bit that allows software to override the WDT enable
configuration bit, only when the configuration bit has
disabled the WDT.
—
Note:
Note:
W = Writable bit
- n = Value at POR Reset
The CLRWDT and SLEEP instructions clear
the WDT and the postscaler, if assigned to
the WDT, and prevent it from timing out
and generating a device RESET condition.
When a CLRWDT instruction is executed
and the postscaler is assigned to the WDT,
the postscaler count will be cleared, but the
postscaler assignment is not changed.
CONTROL REGISTER
U-0
—
U-0
—
PIC18CXX2
U-0
—
DS39026C-page 183
SWDTEN
R/W-0
bit 0