Support TLC5940

[sfranzyshen]

I would like to help to get the TLC5940 support started ... but I am confused as to how to. Is there anyone else who is working on this (tlc5940) support or another chip that I could see how adding a chip is done? Is there a mailing list or forum where developers meet?

[focalintent]

There's only two of us on development (intentionally keeping the size small, so no open dev list - just a g+ community for support). I have a tlc5940 setup here to start putting support in for it. The bigger problem with the tlc5940 is that it is a 12bit chipset - and all the rgb/hsv work internally is 16 bit, while I have a plan for faking it with 8bit support getting (efficient) 16bit versions of the hsv and rgb classes is also something we'll need to get done.

[sfranzyshen]

16bit versions of the hsv and rgb classes is also something we'll need to get done.

I'm guessing you mean 12bit?

[focalintent]

No, I mean 16-bit. I'm not going to try to support/do 12-bit math for the CRGB and CHSV classes (the cpus that we support, that i'm often hand-writing assembly for, have 8 bit math instructions and 16 bit math instructions (and sometimes 32 bit math instructions), but not 12 bit). Also - memory management for 12-bit structures is a nightmare, 16-bit would actually be more efficient all around. We can dither 16-bit CHSV/CRGB classes down to 12-bit to write out to things like the tlc5940 - but i'm also expecting to (eventually) see 16-bit rgb leds in the next year or two, if the controllers aren't out there already, so i'm thinking ahead as well.

[tobiasebsen]

+1 for 12-bit support !!

I have a 12-bit-per-channel chipset (not TLC5940) from a Chinese manufacturer that I would like to use. I was considering making some changes to clockless.h myself, but I'd much rather have it done by someone who knows it well. Thanks.

[focalintent]

@tobiasebsen what chipset do you have? If it's the LPD1886 - I have a strip of those as well and will want to be adding support in there too.

[tobiasebsen]

It's a completely new chip called TM-GW6205. It has 3 channels of 12 bits.
As you said, there may be comming a lot more 12 or 16 bit controllers in the future, so it's best to make some generic support for these chips. Maybe supporting both byte or short data by ether shifting left or right?

[focalintent]

There's a separate issue for the CHSV16/CRGB16 - which is the "generic support" - however, each specific chip will need its own configuration and such beyond that.

[focalintent]

Also - if you have a datasheet for the TM-GW6205 - could you create a new issue for the TM-GW6205 support and a link to the datasheet (if not the datasheet itself)

[tobiasebsen]

Well, I'm not sure that I am allowed to post the datasheet publicly since I got it directly from the manufacturer. Also, the clip isn't available for customers yet.

My point is just that 12-bit support would be nice for me and possibly for supporting more future chipsets.

[focalintent]

Could you email me the data sheet (danielgarcia at gmail)? If it's straightforward enough I can do a quick and dirty prototype for you (doing 8-12bit mapping). (Technically speaking, it won't be 12 bit support, it'll be 16 bit support, but easy to dither down to it :)

[tobiasebsen]

thanks!

[sfranzyshen]

I have noticed some changes in fastled2.1 (Preliminary test support) for the GW6205 (12bit) chipset ... it looks as if you have a work around for the 8bit - 12bit mapping ... couldn't the same be done for the tlc5940?

[focalintent]

If the only thing holding back tlc5940 support was 12 bit - sure, however the tlc5940 uses a different protocol than anything else I'm supporting, and requires some extra changes,while the ge6205 (which is only supported for avr at the moment, because someone has a test setup) is nearly identical to the ws2812 outside of being 12bit and a slight shift of timing.

(Also, I both have a day job and am currently traveling so I don't have access to my tl5940 parts).

[sfranzyshen]

I didn't mean to question your quantity of work. I (and so many others) are grateful for all of the work your team is doing. I didn't realize the extent of the differences between the tlc59xx and other chipsets. So, I apologies if I was coming off as pushy ...