Page 2 of 3 FirstFirst 123 LastLast
Results 11 to 20 of 26

Thread: WS2811 pixel compatibility

  1. #11
    Join Date
    Oct 2011
    Location
    Elizabeth City, NC
    Posts
    706
    Post Thanks / Like

    Default Re: WS2811 pixel compatibility

    Hey Jim,

    If I were to purchase the following strips (http://www.aliexpress.com/product-fm...olesalers.html) based on WS2811, would these work with my E681 that I built back in February? Do I need to upgrade any firmware, or just select 1804 as the pixel type in the controller? Thanks!
    [SIZE=3][B]8000 + E1.31 Channels (5x E68x controllers)
    128 Renard Channels[/SIZE][/B]
    sequencing with LightShow Pro 2.8 and/or Vixen 3 (using xLights scheduler)
    2 x Pixel Mega Trees, RGB Pixel Roofline, 2 x RGB Pixel Spinners, 11 x Pixel Bushes, 6 x GECE Icicle Arches, 16 x RGB Mini Trees, 2 x Vertical Pixel Poles,
    12 x 10w RGB Floods, 160 Strobes controlled by Arduino
    [URL="http://www.controlthelights.net"]http://www.controlthelights.net[/URL]

  2. #12
    Join Date
    Dec 2009
    Posts
    1,208
    Post Thanks / Like

    Default Re: WS2811 pixel compatibility

    Quote Originally Posted by jaywalk101 View Post
    Hey Jim,

    If I were to purchase the following strips (http://www.aliexpress.com/product-fm...olesalers.html) based on WS2811, would these work with my E681 that I built back in February? Do I need to upgrade any firmware, or just select 1804 as the pixel type in the controller? Thanks!
    You would need to update the firmware, it will be available on the web site soon.
    The Sandevices E680/E681/E682 Pixel Controllers, part of the[SIZE=3] [COLOR=red]P[/COLOR][COLOR=orange]I[/COLOR][COLOR=blue]X[/COLOR][COLOR=lime]E[/COLOR][COLOR=magenta]L[/COLOR] [COLOR=red]P[/COLOR][COLOR=lime]R[/COLOR][COLOR=blue]O[/COLOR][COLOR=red]J[/COLOR][COLOR=magenta]E[/COLOR][COLOR=cyan]C[/COLOR][COLOR=red]T[/COLOR]
    [URL="http://www.sandevices.com"]www.sandevices.com[/URL][/SIZE] <-email jim at

  3. #13
    Join Date
    Dec 2009
    Posts
    1,208
    Post Thanks / Like

    Default Re: WS2811 pixel compatibility

    Quote Originally Posted by Matt_Edwards View Post
    Jin are you implementing a NRZ protocol as per the data sheet or the Pseudo NRZ as per Tabor testing over at ACL?

    Tabor suggests
    1 ____
    1 => _2 3 4 5 Ie 4 out of 5 bits are high

    _ 2 3 4 5
    0 =>1 _____ Ie 4 out of 5 bits are low
    First of all, I don't think this signalling scheme is NRZ. Basically, all of these pixels (1804 and 2811 and even the GE ColorEffects chips) work essentially the same way. There is a low-to-high transition at the start of each bit cell, then at the center of the bit cell the chip samples the data line to determine if the bit is a 1 or a 0. So all that's required is that some time after the start of the bit cell, and prior to the center of the bit cell, the sender has to (in the case of a 0) return the data line to 0. In the case of a 1 the sender must return the data line to 0 some time *after* the mid-point of the bit cell.

    The 1804s recommended timing uses a scheme which essentially divided the bit cell into three segments. For a nominal 800kbps data rate, the bit cell is 1250ns long. For an 1804 the recommendation was to send 833ns high (2/3) followed by 417ns low (1/3) for a 1 or 417 ns high followed by 833ns low for a 0.

    The WS2811 recommended timing essentially divides the bit cell into fifths. A 1 is sent as 1000ns high (4 segments) followed by 250ns low (1 segment), while a 0 is sent as 250ns high and 1000 ns low. The fact is that either approach will work, the only thing the pixel chip really cares about is the state of the data line at 625ns.

    The "1804" apprpach has the advantage that less bandwidth is required on the wiring between pixels since the narrowest pulse we are ever sending is 417ns, while the 2801 technique requires more bandwidth since we are sending 250ns pulses. OTOH, the 2811 technique has better noise immunity since the transition time of the data line is farther away from the sample point.

    Both data sheets spec timings as +/- 150ns. So let's look at the worst case:

    With an 1804, worst case is a 0 sent as 567ns high (417+150) followed by a transition to low. That means the time where the data line transitions from 1 to 0 (567ns) is only 58ns from the point where the chip samples the data line (625ns). With a 2811, say a 0 is sent as 400ns high (250+150). Now there's still 225ns between the time the data line transitions to 0 and the sample point, so much better in terms of noise immunity.

    At this point I'm using the WS2811 recommended timing for both 2811s and 1804s, and the 1804s appear to be happy. Likewise the 2811s will work with the 1804 timing recommendations as long as the data rate is very close to 800kbps.
    Last edited by jstjohnz; 05-30-2012 at 02:37 AM.
    The Sandevices E680/E681/E682 Pixel Controllers, part of the[SIZE=3] [COLOR=red]P[/COLOR][COLOR=orange]I[/COLOR][COLOR=blue]X[/COLOR][COLOR=lime]E[/COLOR][COLOR=magenta]L[/COLOR] [COLOR=red]P[/COLOR][COLOR=lime]R[/COLOR][COLOR=blue]O[/COLOR][COLOR=red]J[/COLOR][COLOR=magenta]E[/COLOR][COLOR=cyan]C[/COLOR][COLOR=red]T[/COLOR]
    [URL="http://www.sandevices.com"]www.sandevices.com[/URL][/SIZE] <-email jim at

  4. #14
    Join Date
    Sep 2008
    Location
    Baulkham Hills, NSW
    Posts
    2,605
    Post Thanks / Like

    Default Re: WS2811 pixel compatibility

    Thanks for your explanation. Not being NRZ make sense, as the chip need to synchronise its free running oscilltor using a very basic clock recovery mechanism. ( That I undestand well from my digital old Modulator / Demodultor days).
    This may also explain why the 2811 is cheap.
    However it added a level of complexity to the data stream creation as the AVR SPI is real NRZ. Food for thought.
    [B][I]Matt[/I][/B]

    You too can become a Supporting member of DIYC.
    Check it out [URL="http://doityourselfchristmas.com/forums/payments.php"]here[/URL]

    I record my Blinky Flashy travels here: [URL="http://MyNoelLights.com"]MyNoelLights.com[/URL]

  5. #15
    Join Date
    Mar 2010
    Location
    Albion Park NSW Australia
    Posts
    287
    Post Thanks / Like

    Default Re: WS2811 pixel compatibility

    Thanks Jim your explanation is greatly appreciated
    [SIZE="4"][B][URL="http://www.averyeddyxmas.com"]WWW.[COLOR="Red"]A[/COLOR][COLOR="Green"]VERY[/COLOR][COLOR="RoyalBlue"]EDDY[/COLOR][COLOR="DarkOrchid"]XMAS[/COLOR].com[/URL][/SIZE][/B]

    [url]http://forums.auschristmaslighting.com/index.php[/url]

    Download the AusChristmasLighting 101 manual from [url]http://auschristmaslighting.com/forums/index.php/topic,1889.0.html[/url]

    Your just jealous because the voices only talk to me

  6. #16
    Join Date
    Dec 2009
    Posts
    1,208
    Post Thanks / Like

    Default Re: WS2811 pixel compatibility

    There is a new firmware version on the web site for the E68x controllers that adds support for the 2811s and also the 880x, and 981x series pixels. This version also includes the dithering to achieve 8-bit dimming with the 6803 pixels. Right now it is available as an .eeprom file, which must be loaded using a Parallax Prop Plug programmer. The version that will install over the lan without requiring a programmer will be up soon.
    The Sandevices E680/E681/E682 Pixel Controllers, part of the[SIZE=3] [COLOR=red]P[/COLOR][COLOR=orange]I[/COLOR][COLOR=blue]X[/COLOR][COLOR=lime]E[/COLOR][COLOR=magenta]L[/COLOR] [COLOR=red]P[/COLOR][COLOR=lime]R[/COLOR][COLOR=blue]O[/COLOR][COLOR=red]J[/COLOR][COLOR=magenta]E[/COLOR][COLOR=cyan]C[/COLOR][COLOR=red]T[/COLOR]
    [URL="http://www.sandevices.com"]www.sandevices.com[/URL][/SIZE] <-email jim at

  7. #17
    Join Date
    Oct 2008
    Location
    San Jose, CA
    Posts
    10,282
    Post Thanks / Like

    Default Re: WS2811 pixel compatibility

    Quote Originally Posted by jstjohnz View Post
    There is a new firmware version on the web site for the E68x controllers that adds support for the 2811s and also the 880x, and 981x series pixels. This version also includes the dithering to achieve 8-bit dimming with the 6803 pixels. Right now it is available as an .eeprom file, which must be loaded using a Parallax Prop Plug programmer. The version that will install over the lan without requiring a programmer will be up soon.

    Great support as always sir! Is there any other reason to upgrade my existing 681's if I'm not using those pixels? (i.e. bug fixes, etc)
    Brian

    Christmas in San Jose! - WEB - FB - VIDEOS
    Halloween in San Jose! - FB
    2015 Halloween Show - Planning now - hopefully some house projection...
    2015 Christmas Show - 5x E681-12, 1x 6804, Ren48LSD, 3x RenSS16, 1x Falcon16v2 (w/expander), 24x90 WS2811 pixel MT (James MT Strips), 12x DIYC Floods, SuperPixelStar, 3x Pixel Arches, PixaBulb House outline

    Ignorance is Temporary - Stupidity is Forever...

  8. #18
    Join Date
    Nov 2010
    Location
    Placerville, CA
    Posts
    2,198
    Post Thanks / Like

    Default Re: WS2811 pixel compatibility

    Excuse my ignorance on things Prop, but is the .eeprom fromat proprietary to the Prop programmer? I had visions on updating a really old eeprom using a Nedham programmer (yes they are out of business, and yes it does support the PROM, and yes I have the adapter and personality card.)

    I am familar with .bin, .hex, .rom, and a few others that escape me, but I've NOT seen .eeprom before. Any ideas on how I might get a programmer to choke down a .eeprom file??
    [I][SIZE=2]"Beam me up Scotty, there are only limited pockets of intelligent life on this planet!!"[/SIZE][/I]
    Communicating humor in a text only medium is an art form subject to imprecise interpretation by the audience...

  9. #19
    Join Date
    Dec 2009
    Posts
    1,208
    Post Thanks / Like

    Default Re: WS2811 pixel compatibility

    Quote Originally Posted by budude View Post
    Great support as always sir! Is there any other reason to upgrade my existing 681's if I'm not using those pixels? (i.e. bug fixes, etc)
    No reason to upgrade if you don't use the 6803s or the new pixel types.
    The Sandevices E680/E681/E682 Pixel Controllers, part of the[SIZE=3] [COLOR=red]P[/COLOR][COLOR=orange]I[/COLOR][COLOR=blue]X[/COLOR][COLOR=lime]E[/COLOR][COLOR=magenta]L[/COLOR] [COLOR=red]P[/COLOR][COLOR=lime]R[/COLOR][COLOR=blue]O[/COLOR][COLOR=red]J[/COLOR][COLOR=magenta]E[/COLOR][COLOR=cyan]C[/COLOR][COLOR=red]T[/COLOR]
    [URL="http://www.sandevices.com"]www.sandevices.com[/URL][/SIZE] <-email jim at

  10. #20
    Join Date
    Dec 2009
    Posts
    1,208
    Post Thanks / Like

    Default Re: WS2811 pixel compatibility

    Quote Originally Posted by CaptKirk View Post
    Excuse my ignorance on things Prop, but is the .eeprom fromat proprietary to the Prop programmer? I had visions on updating a really old eeprom using a Nedham programmer (yes they are out of business, and yes it does support the PROM, and yes I have the adapter and personality card.)

    I am familar with .bin, .hex, .rom, and a few others that escape me, but I've NOT seen .eeprom before. Any ideas on how I might get a programmer to choke down a .eeprom file??
    The .eeprom file I believe is a byte-for-byte image of what's to be written to the first 32KB of the eeprom. The file, therefore, is exactly 32K bytes long. I should have the utility available for download soon that allows you to send the .eeprom file to the controller via the lan connection, so no programmer required when doing it that way.
    The Sandevices E680/E681/E682 Pixel Controllers, part of the[SIZE=3] [COLOR=red]P[/COLOR][COLOR=orange]I[/COLOR][COLOR=blue]X[/COLOR][COLOR=lime]E[/COLOR][COLOR=magenta]L[/COLOR] [COLOR=red]P[/COLOR][COLOR=lime]R[/COLOR][COLOR=blue]O[/COLOR][COLOR=red]J[/COLOR][COLOR=magenta]E[/COLOR][COLOR=cyan]C[/COLOR][COLOR=red]T[/COLOR]
    [URL="http://www.sandevices.com"]www.sandevices.com[/URL][/SIZE] <-email jim at

Page 2 of 3 FirstFirst 123 LastLast

Bookmarks

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •