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  1. #1
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    Default 16-bit version of the WS2801 chip

    I've been using the WS2801 chips for a while now but I'm struggling to get my lights fading smoothly with only 256 steps.
    Does anyone know if there's a 16-bit version? Google didn't turn up any results but I don't have a part number to search on.

    I have also considered dithering the normal 8-bit ones but I'm not sure if I can get the refresh rate high enough for that to work well.
    I'd prefer an actual 16-bit chip if one exists.

  2. #2
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    Default Re: 16-bit version of the WS2801 chip

    I do not know if there is a 16bit version of the chip but I wonder why you need more steps (meaning more MCU power hungry code).

    Aren't smooth enough the 256 steps?

    Ioannis

  3. #3
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    Default Re: 16-bit version of the WS2801 chip

    Don't know about a 16bit version but I just stumbled across the LDP1886 which is a 3x12bit LED driver.
    That's 4096 levels per channel or 68.7 billion colors.

    I have not looked at the datasheet to see if it's otherwise compatible with the WS2801 etc series.

    /Henrik.

  4. #4
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    Default Re: 16-bit version of the WS2801 chip

    256 steps are alright for color mixing and for big fades but quite often I'll have the lights down to number 3. They are very dim but they can't really fade out with just 3 steps and it looks a bit odd.
    Processing power isn't much of a problem. I use PIC24FJ64GA004 chips to control them which are 16-bit anyway and have plenty of RAM/cycles.

    I've got another one of these that can read 8 x 16-bit 44.1KHz WAV files from an SD card at the same time, mix them with 8-bit volume control and output to 4 x 16-bit DACs.
    The lighting controller has 36 outputs (12 x RGB) but the refresh rate is much lower.

    Thanks for the LDP1886 suggestion 12-bit would still give me 24 steps instead of 3. I'll have a read up on them.

  5. #5
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    Default Re: 16-bit version of the WS2801 chip

    Hmm, I see. For high lumen, high power, sure you need more steps.

    Interesting.

    How are you programming the dsPIC? In C?

    Ioannis

  6. #6
    Join Date
    Sep 2009
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    652

    Default Re: 16-bit version of the WS2801 chip

    PIC24 isn't dsPIC. PIC24 can be programmed in proton basic. I have dongle, but newer try it....
    Or in microbasic, but I don't recommend it. I fon't have nice experience with it.

  7. #7
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    Default Re: 16-bit version of the WS2801 chip

    Sorry, you are right. I misread the PIC having in mind sound applications.

    For MikroBasic I heard a lot, although it is quite impressive by the specs.

    Anyone with experience on Proton about PIC24 is welcome to commend.

    Ioannis

  8. #8
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    652

    Default Re: 16-bit version of the WS2801 chip

    I helped friend with project for university. It had 4 counters(<2Hz, 50% duty) and 4 timers, 16x2 LCD and it was problem to fit all that code in microbasic on pic16f877. Simple code, I thing PBP version had less than 4K.
    It has a lot of futures built in. Also TCP/IP works out of box on dev board, but again lot of overhead code. I have done similar things in PBP, with much less code space.
    I thing that they work a lot on supported futures, so it is really easy to implement lot of things.
    I work a lot with low power stuff(battery operated sensors, etc) and small code that PBP generate is almost always enough to achieve product life as long as battery shelf life. If not, then I do it in ASM.
    So even if I have powered stuff, I'll do it in PBP because I use to it, and it is good enough.
    MicroBasic support string, floating point by default. But I can use simple include for PBP to get just that. Also string functions are really easy to implement using arrays.
    So I don't see benefit by buying MicroBasic. That is my opinion...

  9. #9
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    Default Re: 16-bit version of the WS2801 chip

    I use PHP. I've written a macro style language that outputs ASM30 to MPLAB. I'm working on a proper compiler for PHP to ASM30 as well (written in PHP) but compilers are hard! lol

    I started out writing ASM30 directly which is fine for simple things but it gets very tedious very quick. I don't get on very well with C and PHP is my main language so I wrote a few classes and functions to output ASM30 and haven't looked back since.

  10. #10
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    Default Re: 16-bit version of the WS2801 chip

    Woow.
    Is it published anywhere?

  11. #11
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    Default Re: 16-bit version of the WS2801 chip

    Not at the moment. The macro version was designed specifically for what I'm doing and only supports the few chips I use.
    I do intend to make the proper compiler available online when it's done and I may open source it but it's a long way off yet.

  12. #12
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    Default Re: 16-bit version of the WS2801 chip

    Very interesting indeed!

    Ioannis

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