DMX Transceiver Arduino Nano

// Based on Hendrik Hoelschers dmx code from http://www.hoelscher-hi.de/hendrik/
// Optimized for Arduino Nano



#include <avr/io.h>
#include <stdint.h>
#include <avr/interrupt.h>


// ********************* local definitions *********************
#define DMX_CHANNELS    (6)            //Define the number of DMX values to store

enum {IDLE, BREAK, STARTB, STARTADR};      //DMX states

uint8_t  gDmxState;
uint8_t  *gDmxPnt;
uint16_t DmxCount;

int addr1dummy;
int addr1;
int addr2;
int addr3;
int addr4;
int addr5;
int addr6;
int addr7;
int addr8;
int addr9;

bool bStartDone;

uint8_t  DmxField[DMX_CHANNELS];     //array of DMX vals (raw)
uint16_t DmxAddress;                   //start address

int chOut1 = 3;
int chOut2 = 5;
int chOut3 = 6;
int chOut4 = 9;
int chOut5 = 10;
int chOut6 = 11;

int addrPin1 = A0;
int addrPin2 = A1;
int addrPin3 = A2;
int addrPin4 = A3;
int addrPin5 = A4;
int addrPin6 = A5;
int addrPin7 = 7;
int addrPin8 = 8;
int addrPin9 = 12;

void setup()                           // run once, when the sketch starts
{

// Die Pins 3, 5, 6, 9, 10 und 11 können PWM ausgeben, diese werden als Outputs verwendet.
 pinMode(chOut1, OUTPUT);
 pinMode(chOut2, OUTPUT);
 pinMode(chOut3, OUTPUT);
 pinMode(chOut4, OUTPUT);
 pinMode(chOut5, OUTPUT);
 pinMode(chOut6, OUTPUT);

// Nachfolgende Pins werden für die DIP-Switches verwendet.

 pinMode(A0, INPUT);
 pinMode(A1, INPUT);
 pinMode(A2, INPUT);
 pinMode(A3, INPUT);
 pinMode(A4, INPUT);
 pinMode(A5, INPUT);
 pinMode(7, INPUT);
 pinMode(8, INPUT);
 pinMode(12, INPUT);

// Pullups setzen auf den DIP-Switch-Inputs.

 digitalWrite(A0, HIGH);
 digitalWrite(A1, HIGH);
 digitalWrite(A2, HIGH);
 digitalWrite(A3, HIGH);
 digitalWrite(A4, HIGH);
 digitalWrite(A5, HIGH);
 digitalWrite(7, HIGH);
 digitalWrite(8, HIGH);
 digitalWrite(12, HIGH);


 // Disable interrupts
 cli();

 // 250kbps baud - only works for 16MHz clock frequency. See the ATMega8 datasheet if you are using a different clock speed
 UBRR0H = 0;
 UBRR0L = 3;

 // enable rx and interrupt on complete reception of a byte
 UCSR0B = (1<<RXEN0)|(1<<RXCIE0);
 UCSR0C = (1<<UMSEL01)|(3<<UCSZ00)|(1<<USBS0);

 // Enable interrupts
 sei();

 gDmxState= IDLE;

 uint8_t i;
 for (i=0; i<DMX_CHANNELS; i++)
 {
   DmxField[i]= 0;
 }


 delay(2000);
 bStartDone = 1;


}

void loop()                     // run over and over again

{
 if (bStartDone == 1) // Programm erst nach 2 Sekunden ausführen (Delay in Setup-Routine vorgegeben), um Flicker beim Einschalten zu vermeiden
  {

  if (digitalRead(addrPin1) == 0) {addr1 = 1;} else {addr1 = 0;}
  if (digitalRead(addrPin2) == 0) {addr2 = 2;} else {addr2 = 0;}
  if (digitalRead(addrPin3) == 0) {addr3 = 4;} else {addr3 = 0;}
  if (digitalRead(addrPin4) == 0) {addr4 = 8;} else {addr4 = 0;}
  if (digitalRead(addrPin5) == 0) {addr5 = 16;} else {addr5 = 0;}
  if (digitalRead(addrPin6) == 0) {addr6 = 32;} else {addr6 = 0;}
  if (digitalRead(addrPin7) == 0) {addr7 = 64;} else {addr7 = 0;}
  if (digitalRead(addrPin8) == 0) {addr8 = 128;} else {addr8 = 0;}
  if (digitalRead(addrPin9) == 0) {addr9 = 256;} else {addr9 = 0;}

 if ((addr1 + addr2 + addr3 + addr4 + addr5 + addr6 + addr7 + addr8 + addr9) == 0) {addr1dummy = 1;} else {addr1dummy = 0;} // Wenn kein DIP-Schalter auf ON steht, ist die Adresse 1.

  DmxAddress= (addr1dummy + addr1 + addr2 + addr3 + addr4 + addr5 + addr6 + addr7 + addr8 + addr9);  //DMX-Adresse setzen

  analogWrite(chOut1, DmxField[0]);
  analogWrite(chOut2, DmxField[1]);
  analogWrite(chOut3, DmxField[2]);
  analogWrite(chOut4, DmxField[3]);
  analogWrite(chOut5, DmxField[4]);
  analogWrite(chOut6, DmxField[5]);

  }
}

// *************** DMX Reception ISR ****************
SIGNAL(USART_RX_vect)
{
uint8_t USARTstate= UCSR0A;                              //get state
uint8_t DmxByte= UDR0;                                    //get data
uint8_t DmxState= gDmxState;                              //just get once from SRAM!!!

if (USARTstate &(1<<FE0))                              //check for break
     {
     UCSR0A &= ~(1<<FE0);                              //reset flag
     DmxCount= DmxAddress;                              //reset frame counter
     gDmxState= BREAK;
     }

else if (DmxState == BREAK)
     {
     if (DmxByte == 0)
           {
           gDmxState= STARTB;                        //normal start code detected
           gDmxPnt= ((uint8_t*)DmxField +1);
           }
     else gDmxState= IDLE;
     }

else if (DmxState == STARTB)
     {
     if (--DmxCount == 0)                              //start address reached?
           {
           gDmxState= STARTADR;
           DmxField[0]= DmxByte;
           }
     }

else if (DmxState == STARTADR)
     {
     uint8_t *DmxPnt;
     DmxPnt= gDmxPnt;
     *DmxPnt= DmxByte;
     if (++DmxPnt >= (DmxField +DMX_CHANNELS))             //all ch received?
           {
           gDmxState= IDLE;
           }
     else gDmxPnt= DmxPnt;
     }
}