To the USB programmer scheme there were added 2x LEDs and 2x resistors. LEDs are not connected same way - to demonstrate options how you could do it.

There are used pins RB6 and RB7 of PIC to control attached LEDs. In a very simple code there is same signal brought into RB6, RB7. But LED will light in opposite - when one is lighting, other one is not.

As a starting point I have used application template compatible with another USB HID bootloader. I have modified all necessary places to change start points from 0x1100 to 0x1000 so it will work with Microchip's USB HID bootloader.

Core part of code is port definition section:

main.c

#define LED1     LATBbits.LATB6
#define LED2     LATBbits.LATB7

and execution part:

main.c

void main(void)
{
     //init TRIS
     TRISBbits.TRISB4=0;
     TRISBbits.TRISB5=0;
     TRISBbits.TRISB6=0;
     TRISBbits.TRISB7=0;
     //infinity loop
     while(1)
     {
          LED1=1;           //simple LED Blinking
          LED2=1;           //simple LED Blinking
          Delay10KTCYx(250);
          Delay10KTCYx(250);
          LED1=0;
          LED2=0;
          Delay10KTCYx(250);
          Delay10KTCYx(250);
     }
}

To compile code I have used:

• MPLAB X IDE v1.95 for Windows released on 30.10.2013
• MPLAB C for PIC18 v3.46 in LITE mode released on 3.5.2013

Archive PIC18F2550 Application template package.zip contains:

• PIC18F2550 / PIC18F2455 LED blinker schematics compatible with USB programmer
• user applications template working/compatible with Microchip's USB HID bootloader including compiled PIC18F2550_Application_template_RKA.hex file generated by MPLAB C for PIC18 v3.46 in LITE mode, that you can upload into PIC using USB programmer

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