PIC18LF2221-I/SP Microchip Technology, PIC18LF2221-I/SP Datasheet - Page 265

• Manufacturer Part Number: PIC18LF2221-I/SP
• Description: IC PIC MCU FLASH 2KX16 28DIP
• Manufacturer: Microchip Technology
• Series: PIC® 18Fr

Specifications of PIC18LF2221-I/SP

• Core Size: 8-Bit
• Program Memory Size: 4KB (2K x 16)
• Core Processor: PIC
• Speed: 40MHz
• Connectivity: I²C, SPI, UART/USART
• Peripherals: Brown-out Detect/Reset, HLVD, POR, PWM, WDT
• Number Of I /o: 25
• Program Memory Type: FLASH
• Eeprom Size: 256 x 8
• Ram Size: 512 x 8
• Voltage - Supply (vcc/vdd): 2 V ~ 5.5 V
• Data Converters: A/D 10x10b
• Oscillator Type: Internal
• Operating Temperature: -40°C ~ 85°C
• Package / Case: 28-DIP (0.300", 7.62mm)
• Controller Family/series: PIC18
• No. Of I/o's: 25
• Eeprom Memory Size: 256Byte
• Ram Memory Size: 512Byte
• Cpu Speed: 40MHz
• No. Of Timers: 4
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant

23.2
For PIC18F4321 family devices, the WDT is driven by
the INTRC source. When the WDT is enabled, the
clock source is also enabled. The nominal WDT period
is 4 ms and has the same stability as the INTRC
oscillator.
The 4 ms period of the WDT is multiplied by a 16-bit
postscaler. Any output of the WDT postscaler is
selected by a multiplexer, controlled by bits in Configu-
ration Register 2H. Available periods range from 4 ms
to 131.072 seconds (2.18 minutes). The WDT and
postscaler are cleared when any of the following events
occur: a SLEEP or CLRWDT instruction is executed, the
IRCF bits (OSCCON<6:4>) are changed or a clock
failure has occurred.
FIGURE 23-1:
© 2005 Microchip Technology Inc.
Change on IRCF bits
All Device Resets
INTRC Source
Watchdog Timer (WDT)
WDTPS<3:0>
SWDTEN
CLRWDT
WDTEN
Sleep
WDT BLOCK DIAGRAM
Enable WDT
WDT Counter
Advance Information
128
4
Programmable Postscaler
1:1 to 1:32,768
23.2.1
Register 23-14 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, but only if the configuration bit has
disabled the WDT.
PIC18F4321 FAMILY
Note 1: The CLRWDT and SLEEP instructions
2: Changing the setting of the IRCF bits
3: When a CLRWDT instruction is executed,
CONTROL REGISTER
clear the WDT and postscaler counts
when executed.
(OSCCON<6:4>) clears the WDT and
postscaler counts.
the postscaler count will be cleared.
Reset
DS39689A-page 263
WDT
Reset
Wake-up from
Power-Managed
Modes