PIC16F872-I/SO Microchip Technology, PIC16F872-I/SO Datasheet - Page 101

• Manufacturer Part Number: PIC16F872-I/SO
• Description: IC MCU FLASH 2KX14 EE 28SOIC
• Manufacturer: Microchip Technology
• Series: PIC® 16Fr

Specifications of PIC16F872-I/SO

• Program Memory Type: FLASH
• Program Memory Size: 3.5KB (2K x 14)
• Package / Case: 28-SOIC (7.5mm Width)
• Core Processor: PIC
• Core Size: 8-Bit
• Speed: 20MHz
• Connectivity: I²C, SPI
• Peripherals: Brown-out Detect/Reset, POR, PWM, WDT
• Number Of I /o: 22
• Eeprom Size: 64 x 8
• Ram Size: 128 x 8
• Voltage - Supply (vcc/vdd): 4 V ~ 5.5 V
• Data Converters: A/D 5x10b
• Oscillator Type: External
• Operating Temperature: -40°C ~ 85°C
• Processor Series: PIC16F
• Core: PIC
• Data Bus Width: 8 bit
• Data Ram Size: 128 B
• Interface Type: I2C/SPI/SSP
• Maximum Clock Frequency: 20 MHz
• Number Of Programmable I/os: 22
• Number Of Timers: 3
• Operating Supply Voltage: 4 V to 5.5 V
• Maximum Operating Temperature: + 85 C
• Mounting Style: SMD/SMT
• 3rd Party Development Tools: 52715-96, 52716-328, 52717-734
• Development Tools By Supplier: PG164130, DV164035, DV244005, DV164005, PG164120, ICE2000, DM163022
• Minimum Operating Temperature: - 40 C
• On-chip Adc: 5-ch x 10-bit
• Package: 28SOIC W
• Device Core: PIC
• Family Name: PIC16
• Maximum Speed: 20 MHz
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant
• For Use With: XLT28SO-1 - SOCKET TRANSITION 28SOIC 300MIL309-1073 - ADAPTER 28-SOIC TO 28-SOIC309-1024 - ADAPTER 28-SOIC TO 28-DIP309-1023 - ADAPTER 28-SOIC TO 28-DIP
• Lead Free Status / Rohs Status: Lead free / RoHS Compliant

11.12 Watchdog Timer (WDT)
The Watchdog Timer is a free running on-chip RC oscil-
lator, which does not require any external components.
This RC oscillator is separate from the RC oscillator of
the OSC1/CLKI pin. That means that the WDT will run,
even if the clock on the OSC1/CLKI and OSC2/CLKO
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 STATUS regis-
ter will be cleared upon a Watchdog Timer time-out.
The WDT can be permanently disabled by clearing
configuration bit WDTE (Section 11.1).
FIGURE 11-10:
TABLE 11-7:
© 2006 Microchip Technology Inc.
2007h
81h,181h
Legend: Shaded cells are not used by the Watchdog Timer.
Note 1: See Register 11-1 for operation of these bits.
Address
Note:
Config. bits
OPTION_REG
PSA and PS2:PS0 are bits in the OPTION_REG register.
Name
SUMMARY OF WATCHDOG TIMER REGISTERS
WDT Timer
Enable Bit
WATCHDOG TIMER BLOCK DIAGRAM
WDT
From TMR0 Clock Source
(Figure 5-1)
RBPU
Bit 7
(1)
BODEN
INTEDG
Bit 6
0
1
PSA
M
U
X
(1)
T0CS
Bit 5
CP1
0
WDT time-out period values may be found in the Elec-
trical Specifications section under parameter #31. Val-
ues for the WDT prescaler (actually a postscaler, but
shared with the Timer0 prescaler) may be assigned
using the OPTION_REG register.
T0SE
Bit 4
CP0
Time-out
8 - to - 1 MUX
MUX
Note 1: The CLRWDT and SLEEP instructions
WDT
Postscaler
2: When a CLRWDT instruction is executed
1
PWRTE
8
clear the WDT and the postscaler, if
assigned to the WDT, and prevent it from
timing out and generating a device
RESET condition.
Bit 3
and the prescaler is assigned to the WDT,
the prescaler count will be cleared, but
the prescaler assignment is not changed.
PSA
PSA
(1)
To TMR0 (Figure 5-1)
WDTE
PS2:PS0
Bit 2
PS2
PIC16F872
FOSC1
Bit 1
PS1
DS30221C-page 99
FOSC0
Bit 0
PS0