LED Strips

[Ryan7777]

I have a bunch of experience with the WS2801 based strips, which you can run using shiftout pretty easy. You basically shift in your bits on the data line with each pulse of the clock line if i remember correctly something like this for the WS2801 Strips (my favorite):

noLEDs           CON   32         ' Change this number to number of LEDs in your strip

shftMode        CON   1           ' Shift data out highest bit first. Clock idles low

LEDsDAT         VAR PORTE.0   ' Shift out data port, change as needed

LEDsCLK          VAR PORTE.1   ' Shift out clock port, change as needed 

i                    VAR    Byte     ' Loop variable

Main:

FOR i TO noLEDs                   ' We have to either shift allllllllll the data bits out at once to all LEDs in one SHIFTOUT or for one RGB LED at a time in a loop, much easier this way!, lots of ways to do this.

SHIFTOUT LEDsDAT, LEDsCLK, shftMode, [1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1] 'Shift out 24 bits to one RGB LED at a time - should be all LEDS ON (can be varibles too)

NEXT i                               ' Loop till all LEDs loaded

i = 0                                 ' Please be kind, rewind.

PAUSE 1000                      ' For human eyes to be able to see that them LEDs are ON

FOR i TO noLEDs                ' Rinse, Repeat - but turn them all off this time
 
SHIFTOUT LEDsDAT, LEDsCLK, shftMode, [0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0] 'Shift out 24 bits - should be all LEDS OFF (can be varibles too) 


NEXT i                           ' A little loopy                             

PAUSE 1000                    ' For human eyes to be able to see that them LEDs are OFF (ever wonder if the fridge light is still on when you close the door?)
               
GOTO Main                     ' Do it till the cows come home!

END                              ' My only friend, The end... (fridge door, The Doors, whatever)

The problem is a lot of newer strips use weirder data protocols which are very timing sensitive. You can make them work, but your PIC is probably going to be dedicated to that, with another pic telling it what to do without a lot of work with interrupts and assembly. Thats why I try to stick to WS2801s

ALSO! if you are driving a bunch of LEDs on your strips, like 32/M in my example, you have to have enough current to drive your strips!!! you also may need to buffer the data and clock lines to be able to drive a bunch of LED controller chips too!!!

-Ryan

[gavo]

Hi Ryan,

Thanks for the reply, I am sure I have one of those obscure ones, the crazy part is it flashes no problems without the 5V PSU Connected to it, the only problem is there is not enough current so it is really dim. The Minute we connect the 5V the strips stays on very bright, for the exception of 1 led with flashes on/off

See the connection below,

Regards,

Gavin

[Ryan7777]

After reading what I could of the datasheet, this looks like a variant of the WS2801 to me.

Also looking closer at your code, you may need to set your TRIS to output and input on the proper pins. Something I neglect to do all the time, and sometimes stuff will work without it. But most of the time it's the one thing biting me when my code doesn't work.

I don't know about the pic you're using and don't have the time at the moment to look, but if it has capture and compare modules, those may need switched off too. And again, sometimes simple things like flashing an LED on a pin works great, but try to do anything more demanding and the CCPs and whatever else, ADCs etc. trip me up. So just because you got an LED to blink doesn't always mean everything else is working. Believe me, I know! If there is some unthought of register that needs set, I'll probably forget it and be scratching my head for hours as a result

I have cooked one strip of WS2801 LEDs before by getting some wires crossed. But they are really fairly robust. It's probably only one chip that failed too, so it may just need cut off the string, finding it is another matter. And getting wires crossed is pretty easy as blue is +V and Red is like data or clock, I forget. Black is Vss I'm pretty sure.

At this point I'd get your LCD going and maybe take every pin and set it up as an input and display something like PortB.3 = 1 when you connect an input. For each pin. And do the opposite as well, hookup an LED to every available pin and have them run back in forth like the whole nightrider thing. In other words, make sure your PIC is working first!!!

-Ryan