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  1. #1
    Join Date
    Feb 2013
    Location
    Quebec, Canada
    Posts
    65

    Default NeoPixel (WS2812B) Demo

    In a previous thread (http://www.picbasic.co.uk/forum/showthread.php?t=18431) I've posted an example how to use those addressable RGB leds (WS2812B) aka NeoPixel. I've optimized the code and made a set of include files.

    The NeoPixels can be used with almost any PIC running at 20MHz. The only limit is the available RAM: you need 3 arrays, one for each colour (RGB). The size of each array is the number of leds to control. With a large number of pixels I suggest using a PIC18F. See PicBASIC manual for more information on arrays limits.

    A PIC running @20MHz is more than enough to make almost any animation. The values are pre-computed and then streamed in one shot. You have plenty of time to compute the next sequence unless you want to build a video screen!

    Two gamma correction files are supplied for better fades in or out. One is for PIC18F and one for the others.
    Ref.: https://learn.adafruit.com/led-trick.../the-quick-fix
    See NeoPixelDump.pbp for instructions.

    The demo code show you how to run them on PIC12F683. Now the only limit is your imagination! Be creative!



    Demo code:
    Code:
    '****************************************************************
    '*  Name    : NeoPixelDemo.pbp                                  *
    '*  Author  : Michel Jasmin                                     *
    '*  Notice  : NO Copyright (c) 2014 Michel Jasmin  ;)           *
    '*          : No Rights Reserved                                *
    '*  Date    : 2014-11-29                                        *
    '*  Version : 1.0                                               *
    '*  Notes   : Demo how to use WS2812B (neoPixels) on            *
    '*          : a PIC12F683 @20MHz                                *
    '****************************************************************
    
    #IF __PROCESSOR__ = "12F683"
        #CONFIG
            __config _HS_OSC & _WDT_OFF & _MCLRE_ON & _CP_OFF
        #ENDCONFIG
    
    #ELSE
        #MSG "Wrong Processor selected!"
    #ENDIF
    
    DEFINE OSC 20
    DEFINE NO_CLRWDT 1  ' Don't waste cycles clearing WDT
    
    '------------ Const -------------------------
    
    NEO_NUM     CON 18  'Number of pixels
    
    '------------ Variables -------------------------
    
    NeoGreen    VAR BYTE[NEO_NUM]
    NeoBlue     VAR BYTE[NEO_NUM]
    NeoRed      VAR BYTE[NEO_NUM]
    NeoPixel    VAR BYTE            'Looping variable
    NeoPixValue VAR BYTE            'Value to be bit-banged
    
    '------------ ALIAS -------------------------
    
    NeoPin      VAR GPIO.2
    
    '-----------  Initialization -------------------------------
    
    Clear   ' Clear RAM before entry
    
    ANSEL = 0
    CMCON0 = 7  'Comparator disabled
    CCP1CON = 0
    WPU = 0
    TRISIO.2 = 0 'NeoPin
    
    NeoPin = 0
    
    GOSUB NeoInit
    
    '-----------  Main program -------------------------
    
    Main:
    
        GOSUB NeoPixelDump
        GOSUB NeoPixelRotate
    
        PAUSE 50
    
        GOTO Main
    
    END
    
    NeoInit:
        'Init values for 18 leds string.
        FOR NeoPixel = 0 TO (NEO_NUM - 1)
    
            IF NeoPixel < 3 THEN
                NeoGreen[NeoPixel] = 0
                NeoBlue[NeoPixel] = 0
                NeoRed[NeoPixel] = 64
    
            ELSEIF NeoPixel < 6 THEN
                NeoGreen[NeoPixel] = 0
                NeoBlue[NeoPixel] = 64
                NeoRed[NeoPixel] = 0
    
            ELSEIF NeoPixel < 9 THEN
                NeoGreen[NeoPixel] = 0
                NeoBlue[NeoPixel] = 64
                NeoRed[NeoPixel] = 64
    
            ELSEIF NeoPixel < 12 THEN
                NeoGreen[NeoPixel] = 64
                NeoBlue[NeoPixel] = 0
                NeoRed[NeoPixel] = 0
    
            ELSEIF NeoPixel < 15 THEN
                NeoGreen[NeoPixel] = 64
                NeoBlue[NeoPixel] = 0
                NeoRed[NeoPixel] = 64
            ELSE
                NeoGreen[NeoPixel] = 64
                NeoBlue[NeoPixel] = 64
                NeoRed[NeoPixel] = 0
            ENDIF
    
        NEXT
    
        RETURN
    
    NeoPixelRotate:
        FOR NeoPixel = 0 TO (NEO_NUM - 1)
            NeoGreen[NeoPixel] = NeoGreen[NeoPixel + 1]
            NeoBlue[NeoPixel] = NeoBlue[NeoPixel + 1]
            NeoRed[NeoPixel] = NeoRed[NeoPixel + 1]
        NEXT
    
        NeoGreen[NEO_NUM - 1] = NeoGreen[0]
        NeoBlue[NEO_NUM - 1] = NeoBlue[0]
        NeoRed[NEO_NUM - 1] = NeoRed[0]
    
        RETURN
    
    
    INCLUDE "..\_Include\NeoPixelDump.pbp"
    
    NeoPixelDemo.zipNeoPixelDemo.zip

  2. #2
    Join Date
    Jan 2005
    Location
    Montreal, Quebec, Canada
    Posts
    2,249

    Default Re: NeoPixel (WS2812B) Demo

    Joyeux Halloween! LOL

    Nice work.

    Robert

  3. #3
    Join Date
    Mar 2003
    Location
    Commerce Michigan USA
    Posts
    1,119

    Default Re: NeoPixel (WS2812B) Demo

    Where can I get the file NeoPixelDemo.ZIP as well as the INCLUDE file? I would like to try them.
    Dave Purola,
    N8NTA
    EN82fn

  4. #4
    Join Date
    Sep 2009
    Posts
    657

    Default Re: NeoPixel (WS2812B) Demo

    Scroll down code and you will find link, or click here
    http://www.picbasic.co.uk/forum/atta...7&d=1417555928

  5. #5

    Default Re: NeoPixel (WS2812B) Demo

    That is really nice piece of code, even if i cannot understand the include asm file.

    Have anyone used it with a 16 or 24 led WS2812 ring? (not the B version)

    I've tried with the pic currently have 18F26K22 at 64 Mhz. On a 16 ring or 24 ring, i cannot set up all the led's to be functioned.

    when i set

    Code:
    NEO_NUM     CON 16  'Number of pixels in Cyrcle
    Only 8 out of 16 LED are functioned.

    In case i increase the number, to 29, only 14 LED's are working, then no matter what number i use.....30+, still 14 LED's are light.

    The last two LED's are not working. Have been test it with 24 ring as well, and the last 2 LED's are not working.

    If anyone have experienced the same, would be nice to share your comments.

  6. #6
    Join Date
    May 2013
    Location
    australia
    Posts
    1,496

    Default Re: NeoPixel (WS2812B) Demo

    I've tried with the pic currently have 18F26K22 at 64 Mhz. On a 16 ring or 24 ring, i cannot set up all the led's to be functioned.
    given that the include files expect a 20mhz clock what steps have you taken to compensate for running at more than 3 times the expected speed
    This is more entertaining than Free to Air TV

  7. #7

    Default Re: NeoPixel (WS2812B) Demo

    Ooops havent seen that. I might try a 20 Mhz crystal then. Should be easier.

  8. #8

    Default Re: NeoPixel (WS2812B) Demo

    I used 4Mhz crystal to 4xPLL and it worked. I couldnt see in the datasheet of the PIC18F26K22 any 20Mhz configuration.

    The code is really good. thanks the Author: Michel Jasmin
    Last edited by astanapane; - 12th August 2018 at 20:25.

  9. #9

    Default Re: NeoPixel (WS2812B) Demo

    May i ask something?

    Could i use all this code as a secondary code?

    I'm thinking to use it only as an effect when the PIC is powered up, the RGB led ring to do its pattern.

    But the main program not to be affected by this code.

    DT has given to us the interrupt function of a flashing LED without disturbing the main program.

    But i really dont know how to import all this code or how to use this DT's interrupt method here.

    Could anyone guide me? Thanks a lot.
    Last edited by astanapane; - 17th August 2018 at 12:25.

  10. #10
    Join Date
    May 2013
    Location
    australia
    Posts
    1,496

    Default Re: NeoPixel (WS2812B) Demo

    Could i use all this code as a secondary code
    But the main program not to be affected by this code.
    ?

    using that code it takes about 1mS to send data to 24 ws2812's . so if your main program can tolerate 1mS gaps in processing every 50mS it would work ok

    if you used a more modern chip with a clc module then you could adapt my code
    found here :-
    http://www.picbasic.co.uk/forum/atta...5&d=1508279203
    that updates the leds as a background interrupt driven process with very very little overhead

    see this thread for that and other more efficient possibilities
    http://www.picbasic.co.uk/forum/showthread.php?t=23399

    But i really dont know how to import all this code or how to use this DT's interrupt method here.
    what have you tried ?
    This is more entertaining than Free to Air TV

  11. #11

    Default Re: NeoPixel (WS2812B) Demo

    Many years ago, i did a simple RFID reader program.

    What it does is to read the RFID tag and if the ID number is stored in the PIC's ram, then it will make a port high.

    That is the whole program.

    I haven't tried anything yet to embed the above RGB code. What i would like to do with this code, is to work on the backround as an effect, when:

    The RFID tag is valid: to light the RGB ring in Green, then to continue working on the backround.
    The RFID tag is not valid: to light up the RGB ring in LED.

    I will try without interrupt and i will add the RFID code inside the main of the RGB code. Will let you know.

  12. #12

    Default Re: NeoPixel (WS2812B) Demo

    this is the addition to the main:

    Code:
    serin2 rfid,84,[WAIT($02),str BUF\10]
                                    
    Check_List:
      FOR tagNum = 1 to 3       ' scan through known tags
        FOR idx = 0 TO 9		' scan bytes in tag
        READ (((tagNum-1)*10) + idx), char	' get tag data from table
        IF (char <> buf(idx)) THEN Bad_Char		' compare tag to table
        NEXT
        GOsub Tag_Found			' all bytes match!
    
    Bad_Char:					' try next tag
      NEXT
      
    Bad_Tag:
      tagNum = 0
        FREQOUT porta.3, 1000 */ $100, 115 */ $100	' groan

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