How to Control a Ton of RGB LEDs with Arduino & TLC5940




This video explains how to use the 16 channel PWM controller TLC5940

The CODE:

//Texas Instruments TLC 5940 with Arduino
//www.kevindarrah.com

#include <SPI.h>//Serial Peripheral Interface Library

  byte ch=0, chbit=0, spibit=0, spibyte=0;// variables used by tlc sub routine
  int SINData;//variable used to shift data to the TLC
  byte transferbyte[48];// bytes that are sent out to the tlc5940 via SPI
  // 48 because 16 channels @ 12bits gives 384bits, 384/8 = 48 bytes, 12 bit to 8 bit conversion
  byte DCvalue[32];//0-63, 6 bit DOT Correction Bytes
  int i, j, k, l,m,n; //misc variables
  int green, oldgreen= 2048;//for random animation
  int red, oldred = 2048;//for random animation
  int blue, oldblue = 2048;//for random animation
  int comeback=0, pick_color=0;//for random animation
  //*******************************************************************************************
  //*******************************************************************************************
void setup(){//   MAIN SETUP   MAIN SETUP   MAIN SETUP   MAIN SETUP   MAIN SETUP

  pinMode(2, OUTPUT);//XLAT
  pinMode(3, OUTPUT);//OSC2B GSCLK
  pinMode(4, OUTPUT);//VPRG
  pinMode(11, OUTPUT);//MOSI DATA
  pinMode(13, OUTPUT);//SPI Clock

  //Set up the SPI
  SPI.setBitOrder(MSBFIRST);//Most Significant Bit First
  SPI.setDataMode(SPI_MODE0);// Mode 0 Rising edge of data, keep clock low
  SPI.setClockDivider(SPI_CLOCK_DIV4);//Run the data in at 16MHz/4 - 4MHz

  for(i=0; i<48; i++)//clear out Gray Scale Data
  transferbyte[i]=0; 

  for(i=0; i<32; i++)//set Dot Correction data to max (63 decimal for 6 bit)
  DCvalue[i]=63;  

  Serial.begin(115200);//debugging?

  //set up DOT Correction
  DotCorrection();// sub routine helps 

  noInterrupts();// set up the counters, so don't go into interrupts
  TCCR2A=B00010010;//Timer 2 set to Compare Mode Toggling pin 5 @ 8MHz, Arduino Digital 3
  // TIMER 2 IS GSCLCK
  //Timer 2 prescaler set to 1, 16/1=16 MHz, but toggles pin 5 every other cycle, 8MHz
  TCCR2B=B00000001;

  TCCR1A=B00000000;//Timer 1 doesn't toggle anything, used for counting
  //Timer 1 prescaler set to Fclk/256
  //Why? We need to count 4096 pulses out of Timer 2 - pin 5
  //8 MHz = 1 pulse every 125ns - - 4096 pulses would need 512us
  //Timer 1 runs at 16MHz/256=62.5kHz, we need a match at every 512us
  //Basically, I can get an interrupt to get called every 512us, so...
  // I need to run Timer 2 @ 8MHz for 512us to get 4096 pulses
  // I can't count those pulses directy (too fast) , so
  // I'll count using Timer 1, which makes a count every 16us
  // The counter starts at 0, so we'll set it to 31 to get an interrupt after 512us
  TCCR1B=B00001100;//Mode=CTC with OSCR1A = TOP and 256 as the prescaler
  // Mask set up, will call ISR (Inerrupt Service Routine) for Compare match on A
  TIMSK1=B00000010;
  //These are the match values for the counters
  // 0 here means it will match on one cycle of the clock/prescaler
  OCR1A= 31;//to get our 512us Interrupt
  interrupts();// kick off the timers!
  for(i=0; i<32; i++)//wipe out the data in tlc
  tlc(i, 0);// This is how you update the LEDs, tlc is a subroutine with two inputs
  // tlc(Channel, Value)  Channel in this case is 0-32 and value is 0-4095 duty cycle
  //4095 is 100% ON
  pinMode(5, OUTPUT);//BLANK  We set this pin up here, so it remains in a high impedance
  // state throughout the setup, otherwise the LEDs go crazy!  even if you write this HIGH

 

For more detail: How to Control a Ton of RGB LEDs with Arduino & TLC5940




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