SIRC using an ATmega328

#include 

const int LED1 = 9;
const int LED2 = 12;
const int LED3 = 13;
const int cmdBtn1 = 0;
const int cmdBtn2 = 1;
const int cmdBtn4 = 3;
const int cmdBtn5 = 4;
const int cmdVolUp = 18;
const int cmdVolDn = 19;
const int adrBtn = 1;

int level1 = 1;

void setup() { 

    pinMode(LED1, OUTPUT);
    pinMode(LED2, OUTPUT);
    pinMode(LED3, OUTPUT);
} 

void loop() {

  
    if ( Sirc.commandReady ) {
      Sirc.commandBusy = true;
      if ( Sirc.address == adrBtn ) {
        if ( Sirc.command == cmdBtn1 ) {
          digitalWrite( LED2, HIGH );
        } else if ( Sirc.command == cmdBtn4 ) {
          digitalWrite( LED2, LOW );
        } else if ( Sirc.command == cmdBtn2 ) {
          digitalWrite( LED3, HIGH );
        } else if ( Sirc.command == cmdBtn5 ) {
          digitalWrite( LED3, LOW );
        } else if ( Sirc.command == cmdVolUp ) {
          if (( level1 += 5 ) > 254 ) {
            level1 = 254;
          }
        } else if ( Sirc.command == cmdVolDn ) {
          if (( level1 -= 5 ) < 1 ) {
            level1 = 1;
          }
        }
        analogWrite( LED1, level1 );
      }
      Sirc.command = 0;
      Sirc.commandReady = false;
      Sirc.commandBusy = false;
    }
}