ws2811/2812b

acidice333 · Joined: 14 Oct 2006 Posts: 33

So im trying to play around with getting my WS2812B's working using this code here http://www.insomnialighting.com/code/ws2811.c

and they work on my 18F4550 with the fuses changed to something like this:

temtronic · Posted: Sat Feb 01, 2014 9:42 am

I downloaded that program and it seems ok. The fact it works on the 4550 is great news.
As for running on the 24F PIC....
1) I'd setup the PIC to run speed as the 4550 (IE 48MHz), so that timings should be the same as seen on a scope. Confirm with the 1Hz LED test ! Getting the fuses right can be, well, fun...

2) do not change the ws2811 bit values...go with what works ! changing them changes the timing....(well bit widths and positions)

3) does the 24series default int to 8 bit or 16 ? Again, I don't use them, but that might be an issue.

4)I have to ask, WHY 'upgrade' from ws2801 to ws2811? PICs are cheap, so saving a pin can't be a reason. Can't really save on wiring, can you? 2801s are 24bit as well. Just curious.

hth
jay

jeremiah · Joined: 20 Jul 2010 Posts: 1358

I haven't dug through the entire data sheet, but your comments reference a 32MHz crystal, which usually won't work with PIC24 chips. You can use a 32MHz oscillator chip, but most PIC24 can't use crystals much higher than 24MHz. If you look at page 114, it shows the proper FUSES for 32MHz, but notice it only uses the EC (External Chip) fuse rather than giving an option for HS (High Speed Crystal) fuse like it does for 24MHz and below.

Also, it sometimes helps to be more specific with the #use delay() on some PIC24 chips. Things like #use delay(crystal=20000000,clock=32000000) sometimes help the PCD compiler better lay out the parameters for the PLL.

Ttelmah · Joined: 11 Mar 2010 Posts: 19553

Add one more thing.
The PCD compiler now usually defaults to signed. This causes quite a few problems with drivers.

Best Wishes

bkamen · Posted: Sun Feb 02, 2014 12:00 pm

acidice333 · Joined: 14 Oct 2006 Posts: 33

Thanks for the help.

I'm upgrading from ws2801 to ws2812b because its cheaper in the long run because I need to do 288 of these for a LED table project so I figured I'd try to get this working and go that route than to make 268 more pixel modules ;)

So far so good. I found out there wasn't any SPI activity going on and thats why the ws2812b's weren't working. Ended up being an `int8` cast as signed but I needed unsigned. Works now.