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Topic: Shiftbrite question (Read 763 times) previous topic - next topic


I have two shiftbrites with powered by an external supply and hooked to an Arduino Duemilanova.

I have tried several sample codes and I am unable to get anything but rapidly flashing dim lights.

I have tried the code below and I only get a dim blink every 2 seconds. This makes me think that the shiftbrite requires that I continually pump it new values to keep it lit up. I was under the impression that the light would stay the last color that you send it.

If I remove the delay, I get rapid dim  blinks and still no good color out of the LED.

Here is my code.
Code: [Select]
#define clockpin 13 // CI
#define enablepin 10 // EI
#define latchpin 9 // LI
#define datapin 11 // DI

#define NumLEDs 2

int LEDChannels[NumLEDs][3] = {0};
int SB_CommandMode;
int SB_RedCommand;
int SB_GreenCommand;
int SB_BlueCommand;

void setup() {

  pinMode(datapin, OUTPUT);
  pinMode(latchpin, OUTPUT);
  pinMode(enablepin, OUTPUT);
  pinMode(clockpin, OUTPUT);
  SPCR = (1<<SPE)|(1<<MSTR)|(0<<SPR1)|(0<<SPR0);
  digitalWrite(latchpin, LOW);
  digitalWrite(enablepin, LOW);


void SB_SendPacket() {

   if (SB_CommandMode == B01) {
    SB_RedCommand = 120;
    SB_GreenCommand = 100;
    SB_BlueCommand = 100;

   SPDR = SB_CommandMode << 6 | SB_BlueCommand>>4;
   while(!(SPSR & (1<<SPIF)));
   SPDR = SB_BlueCommand<<4 | SB_RedCommand>>6;
   while(!(SPSR & (1<<SPIF)));
   SPDR = SB_RedCommand << 2 | SB_GreenCommand>>8;
   while(!(SPSR & (1<<SPIF)));
   SPDR = SB_GreenCommand;
   while(!(SPSR & (1<<SPIF)));


void WriteLEDArray() {

   SB_CommandMode = B00; // Write to PWM control registers
   for (int h = 0;h<NumLEDs;h++) {
       SB_RedCommand = LEDChannels[h][0];
       SB_GreenCommand = LEDChannels[h][1];
       SB_BlueCommand = LEDChannels[h][2];

   digitalWrite(latchpin,HIGH); // latch data into registers

   SB_CommandMode = B01; // Write to current control registers
   for (int z = 0; z < NumLEDs; z++) SB_SendPacket();
   digitalWrite(latchpin,HIGH); // latch data into registers


void loop() {

  LEDChannels[0][0] = 1023;
  LEDChannels[0][1] = 0;
  LEDChannels[0][2] = 0;

  LEDChannels[1][0] = 0;
  LEDChannels[1][1] = 0;
  LEDChannels[1][2] = 1023;



Thank you in advance for any support!


Do you have the ShiftBrite ground, the external supply ground, and the Arduino ground all connected together?
Unique RGB LED Modules and Arduino shields: http://www.macetech.com/store


OMG that fixed it.

I can't believe that I overlooked that.



I'm so glad to see that everything actually is working how I expected it to work. :)

I have a bit more confidence in my sanity now.


Glad to hear it's working...I knew almost instantly what was wrong because someone else asked the same question in these forums a few hours ago: http://www.arduino.cc/cgi-bin/yabb2/YaBB.pl?num=1268933348
Unique RGB LED Modules and Arduino shields: http://www.macetech.com/store

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