INTERFACING SWITCH WITH PIC18F4550

Difference between PIC16F I/O and PIC18F I/O:

 PIC 16F Microcontrollers  have two registers to control IO pins, which are TRIS and PORT. TRIS is used to control direction (Input or Output) of each IO pin while PORT is used to Write or Read data from IO pins. Whereas in 18F PIC Microcontrollers there is an additional register, LAT. LAT stands for Port Latch. As in 16F, 18F also uses TRIS register to control direction of each IO pin. LAT register is used to write Output and PORT register is used read Inputs.

Writing Bit by Bit :

TRISC.F0 =1;    // makes 0th bit of PORTC Input

TRISC.F1 =0;   // makes 1st  bit of PORTC Output

PORTB.F3 =1; // Makes 3rd bit of PORTB at Logic High

PORTB.F7 =0; // Makes 7th bit of PORTB at Logic Low 

Mikro C Code for Interfacing Switch :

Figure1: Mikro C code

Simulation :

Figure 2 : Switch Interface with PIC18F4550