How to deal with Digital signal with PIC16F877A

1. Lecture 3 :
Digital I/O & Small Project

2. Agenda
• Why PIC ??? & Why PIC16F877A
• PIC16F877A ports and Pins
• Project 1 “Flasher-1”
• Project 2 “Flasher-2”
• Pull-up & Pull-down Resistors
• Project 3 “Button-1”
• Project 4 “Button-2”

3. Why PIC ? & Why PIC16F877A
Why PIC ???
• PIC is a well-known Microcontroller from a big company ‘Microchip’
• Microchip produce big number of controllers with different features
• There is a lot of online tutorials on PIC family
Why PIC16F877A ??
• Big memory size
• Wide range of Peripheral

4. PIC16F877A Ports : PORTA
PORTA : is a 6-Bit Bidirectional port
PORTA Pins
• RA0 , RA1 : Digital I/O , Analog input
• RA2 : Digital I/O , Analog input , ADC Ref- , Comparator Ref
• RA3 : Digital I/O , Analog input , ADC Ref+
• RA4 : Digital I/O , Comparator 1 output
• RA5 : Digital I/O , Analog input , SPI salve select , Comparator 2 output

5. PIC16F877A Ports : PORTB
PORTB : is an 8-Bit Bidirectional port , with software weak PULL-UP
PORTB Pins
• RB0 : Digital I/O , External Interrupt
• RB1 : Digital I/O
• RB2 : Digital I/O
• RB3 : Digital I/O , Low voltage ICSP programming enable pin
• RB4 : Digital I/O
• RB5 : Digital I/O
• RB6 : Digital I/O , In circuit Debugger & ICSP Programming Clock
• RB7 : Digital I/O , In circuit Debugger & ICSP Programming Data
Note :- RB4 : RB7 have interrupt on-change feature , and only pins configure as
input can cause interrupt to occar.

6. PIC16F877A Ports : PORTC
PORTC : is an 8-Bit Bidirectional port
PORTC Pins
• RC0 : Digital I/O , TMR1 Oscillator output , TMR1 external clock input
• RC1 : Digital I/O , TMR1 Oscillator input , Capture2 input , compare2 , PWM2
• RC2 : Digital I/O , Capture 1 input , Comparator 1 output , PWM 1 output
• RC3 : Digital I/O , SPI clock , I2C clock
• RC4 : Digital I/O , SPI data in , I2C data I/O
• RC5 : Digital I/O , SPI data out
• RC6 : Digital I/O , UART transmitter , USART clock
• RC7 : Digital I/O , UART receiver , USART Data

7. PIC16F877A Ports : PORTD
PORTD : is an 8-Bit Bidirectional port
PORTD Pins
• RD0 : Digital I/O , Parallel Slave port bit 0
• RD1 : Digital I/O , Parallel Slave port bit 1
• RD2 : Digital I/O , Parallel Slave port bit 2
• RD3 : Digital I/O , Parallel Slave port bit 3
• RD4 : Digital I/O , Parallel Slave port bit 4
• RD5 : Digital I/O , Parallel Slave port bit 5
• RD6 : Digital I/O , Parallel Slave port bit 6
• RD7 : Digital I/O , Parallel Slave port bit 7

8. PIC16F877A Ports : PORTE
PORTE : is a 3-Bit Bidirectional port
PORTE Pins
• RE0 : Digital I/O , Analog input , Read control for parallel slave
• RE1 : Digital I/O , Analog input , Write control for parallel slave
• RE2 : Digital I/O , Analog input , chip select control for parallel slave

9. Project 1 “ Flasher-1”
Make project where a LED is connected
to RB0 , This LED is on for
half Second and off for
another half second

10. Project 2 “ Flasher-2”
Make project where an 8 LED is connected To PORTB , half LED is on
for 0.5s and the other is off and After 0.5s the LED is complemented

11. Pull-up & Pull-down Resistors

12. Project 3 “Button-1”
LED is connected to RB0 and button to RD0
When the button is pressed the LED complement
Its Status

13. Project 4 “Button-2”
8 LEDs connected to PORTB and two Switches connected to RA0
and RA1. When Switch1 is pressed the LEDs shift
Right and if Switch2 is pressed the LEDs shift Left

14. Q & A

15. For more information
AZEX Team :
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Mail : M.Bedair@Azhar.Edu.Eg