https://medium.com/jungletronics/pic-18-hello-world-o-f00275279cd0

unit_01_01_blinkingLED.c

/* Project: Unit 01 - IO
      Code: unit_01_01_blinkingLED.c
   Objective:    Let's blink an LED on PORTD's bit 0 and config Button on PORTB's bit 0
                as input (KEY) for future implementation :)
                In my board 8 LEDs are connected to PORTD and 8 buttons are on PORTB
                of PIC18F4520 uC, running under 8 MHZ crystal (set sw1 dip = 9, LEDs on PORTD);
      
      Author:   microgenios, edited by J3
   PIC Lessons: How to Start to Program PIC 18 - Step-by-step for Beginners!
   Hardware:    Development Boards (OPTIONS):
                   PicGenios:   PIC18F4520 chip   ( https://loja.microgenios.com.br/produto/kit-picgenios-pic18f4520-com-gravador-usb-microicd-licen-a-compilador-mikroc-pro-for-pic/23507 )
                   EasyPIC™ 7:  PIC18F45K22 chip  ( https://www.microchip.com/Developmenttools/ProductDetails/TMIK013 )
   Software:    Development Programmer/Debugger:
                                PICkit™ 2         ( http://ww1.microchip.com/downloads/en/DeviceDoc/PICkit%202%20v2.61.00%20Setup%20A.zip )
                          mikroProg suite for PIC ( https://www.mikroe.com/blog/mikroprog-suite-for-pic-version-2-3-1-released )
        PDL:    is a free-format English-like text that describes the flow of control and data in a
                program. PDL is not a programming language. It is a collection of some keywords that enable
                a programmer to describe the operation of a program in a stepwise and logical manner:
              BEGIN
                  Pre-compilation Directives (config PORTB and PORTD as digital) for PIC18F4520 & PIC18F45K22
                  Configure PORTB register bit 0 as digital input (just one button/key)
                  Configure all PORTD as digital output (init all LEDs off)
                  DO FOREVER
                      Turn PORTD reg. bit 0 on
                      Wait .3s
                      Turn PORTD reg. bit 0 off
                      Wait .3s
                  ENDDO
              END
       Date:   Oct 2019
*/

void main() {
                           // For PIC18F45K22
#ifdef PIC18F45K22
       ANSELB = 0;         // Config all the PORTB's pins as digital
       ANSELD = 0;         // Config all the PORTD's pins as digital
                           // For PIC18F4520
#else
       ADCON1 |= 0X0F;     // Config all ADC's pins as digital
#endif

  /* BEGINNING TO CODE FROM HERE! */
  // Button on PORTB RB0
  TRISB.RB0 = 1;           // Config RB0 as Input (1=I:)
  PORTB.RB0 = 1;           // Optional, the MCU do it automatically ;)

  // LEDs on PORTD RD0
  TRISD = 0;               // Config all PORTD's pins as Output (0=0:)
  PORTD = 0;               // Config all PORTD's pins as LOW,
                           // then all LEDs attached to it will be OFF;)

  /* Remember that all pin's are initialize as analogue,
     so we need to config ANSEL (PIC18F45K22) or ADCON1 (PIC18F4520);
     PLEASE GOTO init of this main routine and set directive like this:
     #ifdef/#else/#endif... */

  while(1)
        {
         PORTD.RD0 = 1;     // Turn LED on
         Delay_ms(300);     // delay 300 ms
         PORTD.RD0 = 0;     // Turn LED off
         Delay_ms(300);     // delay 300 ms
        }
}