PIC16F877-20/P Microchip Technology, PIC16F877-20/P Datasheet - Page 59

• 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

1997 Microchip Technology Inc.
Some devices do not have the on-chip brown-out circuit, and in other cases there are some appli-
cations where the Brown-out Reset trip point of the device may not be at the desired level.
Figure 3-10
Each needs to be evaluated to determine if they match the requirements of the application.
Figure 3-10: External Brown-out Protection Circuit 1
Figure 3-11: External Brown-out Protection Circuit 2
Note 1: This brown-out circuit is less expensive, albeit less accurate. Transistor Q1 turns
This circuit will activate reset when V
where Vz = Zener voltage.
Note 1: Internal Brown-out Reset circuitry should be disabled when using this circuit.
2: Internal Brown-out Reset circuitry should be disabled when using this circuit.
3: Resistors should be adjusted for the characteristics of the transistor.
2: Resistors should be adjusted for the characteristics of the transistor.
off when V
and
Figure 3-11
V
DD
•
DD
R1 + R2
is below a certain level such that:
R1
are two examples of external circuitry that may be implemented.
33 k
R1
R2
V
V
DD
DD
= 0.7V
10 k
DD
40 k
goes below (Vz + 0.7V)
40 k
Q1
Q1
Section 3. Reset
PIC16CXXX
MCLR
V
MCLR
PIC16CXXX
V
DD
DD
DS31003A-page 3-9
3