Powering it got it working. Not my brightest moment.
I'm trying to read from the RS485, not write to it. DMX is supposed to be input only, and I'm outputting through USB. Is that not possible?
As for my code, I'm working from the site I linked. Unfortunately, it's a bit above me.
/***********************************************************
* DMX-512 Reception *
* Developed by Max Pierson *
* Version Rev15 9 Oct 2010 *
* Released under the WTFPL license, although I would *
* appreciate Attribution and Share-Alike *
* See blog.wingedvictorydesign.com for the latest version. *
************************************************************/
/******************************* Addressing variable declarations *****************************/
#include <EEPROM.h>
#define NUMBER_OF_CHANNELS 8
//the number of channels we want to receive (8 by default).
#define SWITCH_PIN_0 11 //the pin number of our "0" switch
#define SWITCH_PIN_1 12 //the pin number of our "1" switch
unsigned int dmxaddress = 1; //for some reason it's 7
/* The dmx address we will be listening to. The value of this will be set in the Addressing()
* function and read from EEPROM addresses 510 and 511.
/******************************* MAX485 variable declarations *****************************/
#define RECEIVER_OUTPUT_ENABLE 2
/* receiver output enable (pin2) on the max485.
* will be left low to set the max485 to receive data. */
#define DRIVER_OUTPUT_ENABLE 3
/* driver output enable (pin3) on the max485.
* will left low to disable driver output. */
#define RX_PIN 0 // serial receive pin, which takes the incoming data from the MAX485.
#define TX_PIN 1 // serial transmission pin
/******************************* DMX variable declarations ********************************/
volatile byte i = 0; //dummy variable for dmxvalue[]
volatile byte dmxreceived = 0; //the latest received value
volatile unsigned int dmxcurrent = 0; //counter variable that is incremented every time we receive a value.
volatile byte dmxvalue[NUMBER_OF_CHANNELS];
/* stores the DMX values we're interested in using--
* keep in mind that this is 0-indexed. */
volatile boolean dmxnewvalue = false;
/* set to 1 when updated dmx values are received
* (even if they are the same values as the last time). */
/******************************* Timer2 variable declarations *****************************/
volatile byte zerocounter = 0;
/* a counter to hold the number of zeros received in sequence on the serial receive pin.
* When we've received a minimum of 11 zeros in a row, we must be in a break. */
void setup() {
/******************************* Max485 configuration ***********************************/
pinMode(RECEIVER_OUTPUT_ENABLE, OUTPUT);
pinMode(DRIVER_OUTPUT_ENABLE, OUTPUT);
digitalWrite(RECEIVER_OUTPUT_ENABLE, LOW);
digitalWrite(DRIVER_OUTPUT_ENABLE, LOW); //sets pins 3 and 4 to low to enable reciever mode on the MAX485.
pinMode(RX_PIN, INPUT); //sets serial pin to receive data
/******************************* Addressing subroutine *********************************/
pinMode(SWITCH_PIN_0, INPUT); //sets pin for '0' switch to input
digitalWrite(SWITCH_PIN_0, HIGH); //turns on the internal pull-up resistor for '0' switch pin
pinMode(SWITCH_PIN_1, INPUT); //sets pin for '1' switch to input
digitalWrite(SWITCH_PIN_1, HIGH); //turns on the internal pull-up resistor for '1' switch pin
/* Call the addressing subroutine. Three behaviors are possible:
* 1. Neither switch is pressed, in which case the value previously stored in EEPROM
* 510 and 511 is recalled,
* 2. Both switches are pressed, in which case the address is reset to 1.
* 3. Either switch is pressed (but not both), in which case the new address may
* be entered by the user.
*/
//set this equal to a constant value if you just want to hardcode the address.
dmxaddress = 1;
/******************************* USART configuration ************************************/
Serial.begin(250000);
/* Each bit is 4uS long, hence 250Kbps baud rate */
cli(); //disable interrupts while we're setting bits in registers
bitClear(UCSR0B, RXCIE0); //disable USART reception interrupt
/******************************* Timer2 configuration ***********************************/
//NOTE: this will disable PWM on pins 3 and 11.
bitClear(TCCR2A, COM2A1);
bitClear(TCCR2A, COM2A0); //disable compare match output A mode
bitClear(TCCR2A, COM2B1);
bitClear(TCCR2A, COM2B0); //disable compare match output B mode
bitSet(TCCR2A, WGM21);
bitClear(TCCR2A, WGM20); //set mode 2, CTC. TOP will be set by OCRA.
bitClear(TCCR2B, FOC2A);
bitClear(TCCR2B, FOC2B); //disable Force Output Compare A and B.
bitClear(TCCR2B, WGM22); //set mode 2, CTC. TOP will be set by OCRA.
bitClear(TCCR2B, CS22);
bitClear(TCCR2B, CS21);
bitSet(TCCR2B, CS20); // no prescaler means the clock will increment every 62.5ns (assuming 16Mhz clock speed).
OCR2A = 64;
/* Set output compare register to 64, so that the Output Compare Interrupt will fire
* every 4uS. */
bitClear(TIMSK2, OCIE2B); //Disable Timer/Counter2 Output Compare Match B Interrupt
bitSet(TIMSK2, OCIE2A); //Enable Timer/Counter2 Output Compare Match A Interrupt
bitClear(TIMSK2, TOIE2); //Disable Timer/Counter2 Overflow Interrupt Enable
sei(); //reenable interrupts now that timer2 has been configured.
} //end setup()
void loop() {
// the processor gets parked here while the ISRs are doing their thing.
if (dmxnewvalue == 1) { //when a new set of values are received, jump to action loop...
action();
dmxnewvalue = 0;
dmxcurrent = 0;
zerocounter = 0; //and then when finished reset variables and enable timer2 interrupt
i = 0;
bitSet(TIMSK2, OCIE2A); //Enable Timer/Counter2 Output Compare Match A Interrupt
}
} //end loop()
//Timer2 compare match interrupt vector handler
ISR(TIMER2_COMPA_vect) {
if (bitRead(PIND, PIND0)) { // if a one is detected, we're not in a break, reset zerocounter.
zerocounter = 0;
}
else {
zerocounter++; // increment zerocounter if a zero is received.
if (zerocounter == 20) // if 20 0's are received in a row (80uS break)
{
bitClear(TIMSK2, OCIE2A); //disable this interrupt and enable reception interrupt now that we're in a break.
bitSet(UCSR0B, RXCIE0);
}
}
} //end Timer2 ISR
ISR(USART_RX_vect){
dmxreceived = UDR0;
/* The receive buffer (UDR0) must be read during the reception ISR, or the ISR will just
* execute again immediately upon exiting. */
dmxcurrent++; //increment address counter
if(dmxcurrent > dmxaddress) { //check if the current address is the one we want.
dmxvalue[i] = dmxreceived;
i++;
if(i == NUMBER_OF_CHANNELS) {
bitClear(UCSR0B, RXCIE0);
dmxnewvalue = 1; //set newvalue, so that the main code can be executed.
}
}
} // end ISR
void action() {
/*********** Put what you want the code to do with the values (dmxvalue) here *************
* example code: print out the received values to the serial port, and set PWM pins 5 and 6
to the first two values received. You can take this code out and put your own in.*/
//begin example code
//for(byte j = 0; j < NUMBER_OF_CHANNELS; j++) {
Serial.println(dmxvalue[0],DEC);
return; //go back to loop()
} //end action() loop
unsigned int Addressing() {
dmxaddress = 1;
}
Now, it's sort of working. I plug it all in and open the serial connection and turn on the DMX, but it spams 1, 0 and an occasional number around 137, regardless of what I set the outputs in LightsUp! to. Do you have any idea what might be going wrong? How can I troubleshoot it further? If it's outputting to serial that's the problem, it works just as well for me to output through an analog or digital pin.
