LDP8806 RGB LED Light Strip

[m_flfl]

http://arduino.cc/forum/index.php?PH...&topic=83073.0

[Atom058]

Hello Everyone - Thanks for your posts. I am sorry that I droped out of this, but I am now in Mexico dealing with a family illness. In my spare time, I have scoured all the forums, blogs, posts that I could find and I finally came across some obscure post that broke the ice for me. I will explain what I found... For the LDP8806 LED strip, the thing that threw me off was that there was no "latch" pin. Just 4 wires: +5V, Gnd, Data and Clock. At first, I thought it was I2C, but that did not pan out. I then discovered that you have to send 3 bytes for each LED on the strip (using SHIFTOUT). 1 byte for each of R, G & B. If you want the particular LED to be turned on, the high bit (bit 7) should always be set to 1. The remaining 7 bits will determine the brightness of that LED (that's the nice thing about this chip is that it has built-in PWM). So, if you sent an LED a %10000000, you would activate that LED, but it would be set at 0 brightness (off). Send %11111111 would be on at full strength. OK, lets say you have a 1M strip. That will have 32 RGB LEDs on it and you want the output to be white. You would send:

GreenLED = %11111111
RedLED = %11111111
BlueLED = %11111111

for icnt = 1 to 32
shiftout dp1, cp1, 1, [GreenLED/8, RedLED/8, BlueLED/8]
Next

That loads all of the LEDs on the strip with the information. Now here's the jewel... To get it to latch (display), you send 3 %00000000's (SHIFTOUT DP1, CP1, 1, [%00000000, %00000000, %00000000]) one time and that gets sent down the line and you now have a bright white strip. That is pretty much it. Now you can use your imagination and get all kinds of cool effects - I have! Hope that helps! Have fun! Jeff

[cncmachineguy]

Good stuff Jeff, Thanks for clearing this up!!