PIC16F877-20/P Microchip Technology, PIC16F877-20/P Datasheet - Page 488

• Manufacturer Part Number: PIC16F877-20/P
• Description: IC MCU FLASH 8KX14 EE 40DIP
• Manufacturer: Microchip Technology
• Series: PIC® 16Fr

Specifications of PIC16F877-20/P

• Core Size: 8-Bit
• Program Memory Size: 14KB (8K x 14)
• Core Processor: PIC
• Speed: 20MHz
• Connectivity: I²C, SPI, UART/USART
• Peripherals: Brown-out Detect/Reset, POR, PWM, WDT
• Number Of I /o: 33
• Program Memory Type: FLASH
• Eeprom Size: 256 x 8
• Ram Size: 368 x 8
• Voltage - Supply (vcc/vdd): 4 V ~ 5.5 V
• Data Converters: A/D 8x10b
• Oscillator Type: External
• Operating Temperature: 0°C ~ 70°C
• Package / Case: 40-DIP (0.600", 15.24mm)
• Controller Family/series: PIC16F
• No. Of I/o's: 33
• Eeprom Memory Size: 256Byte
• Ram Memory Size: 368Byte
• Cpu Speed: 20MHz
• No. Of Timers: 3
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant
• For Use With: 444-1001 - DEMO BOARD FOR PICMICRO MCU
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant, Lead free / RoHS Compliant

PICmicro MID-RANGE MCU FAMILY
26.3
DS31026A-page 26-4
Watchdog Timer (WDT) Operation
During normal operation, a WDT time-out generates a device RESET. If the device is in SLEEP
mode, a WDT time-out causes the device to wake-up and continue with normal operation, this is
known as a WDT wake-up. The WDT can be permanently disabled by clearing the WDTE con-
figuration bit.
The postscaler assignment is fully under software control, i.e., it can be changed “on the fly” dur-
ing program execution.
In
final desired prescaler is other then 1:1. If the final prescaler value is 1:1, then a temporary pres-
cale value is set (other than 1:1), and the final prescale value is set in the last modification of the
OPTION_REG. This sequence must be followed since the value in the TMR0 prescaler is
unknown, and is being used as the WDT postscaler. If the OPTION_REG is changed without this
code sequence, the time before a WDT reset is unknown.
Example
Note:
26-1, the first modification of the OPTION_REG does not need to be included if the
To avoid an unintended device RESET, the following instruction sequence (shown
in
Timer0 to the postscaler of the WDT. This sequence must be followed even if the
WDT is disabled.
Example
26-1) must be executed when changing the prescaler assignment from
1997 Microchip Technology Inc.