Ws281x SPI connection device type

Wolph · 4. Juli 2016

I've been fiddling around with the config quite a bit and I'm currently trying this device but it appears to be doing nothing at all. I should note that I'm running a Pi-1B here.

Code

"device" :
    {
        "name"       : "MyHyperionConfig",
        "type"       : "ws2812spi",
        "colorOrder" : "grb",
        "output"     : "/dev/spidev0.0",
        "rate"       : 3800000
    },

The output when hyperion is and isn't running is currently:

Code

# vcgencmd measure_clock core
frequency(1)=250000000

I'm unable to produce any output using SPI at the moment. To be sure the led strip is functioning correctly I have tried the strip on pin 18 using this device which works:

Code

{
     "name"       : "MyHyperionConfig",
     "type"       : "ws2812spi",
     "colorOrder" : "grb"
 },

Rick164 · 4. Juli 2016

Would upload the RPi config.txt to somewhere like gist so @penfold42 can compare it

Wolph · 4. Juli 2016

Oops, forgot about that. It's mostly stock though, with the suggested changes from this topic: [MEDIA=gist]3dde4e42a3d710eba1f5e152161682f4[/MEDIA]

penfold42 · 5. Juli 2016

Interesting - I've never test on openelec.

I think one of my Pi's has it setup to multi boot so I'll try to replicate it next week.

Does configuring fewer LEDs work better ? Maybe the OE kernel has SPI issues with more LEDs.

I am abusing the SPI device a bit - there's an assumption the kernel will use DMA and send all the led data in one continuous burst

Wolph · 5. Juli 2016

Zitat von penfold42

Interesting - I've never test on openelec.

I'm actually running Raspbian 8 (Jessie). A stock install specifically for Hyperion a few weeks ago so it shouldn't contain anything out of the ordinary..

Zitat

Does configuring fewer LEDs work better ? Maybe the OE kernel has SPI issues with more LEDs.

I am abusing the SPI device a bit - there's an assumption the kernel will use DMA and send all the led data in one continuous burst

Just for completeness I've tried with 32 leds and I'm not able to get it to do anything anymore unfortunately.

Could it be that I need a level shifter for it to work through the MOSI pin?

penfold42 · 5. Juli 2016

Thanks - I have that too on a spare pi.

If you're hardware works with a PWM output it should be fine on the MOSI pin

Wolph · 7. Juli 2016

Since I'm unable to get it do do anything (besides a randomly colored first led) I have ordered a few level shifters just to be sure.

@penfold42 could it be that I'm setting an incorrect rate? Is there any way to debug why it's not working properly? I'm currently using the config from your commit message: https://github.com/hyperion-pr…29edb413685e700d2f1714212

penfold42 · 7. Juli 2016

It's difficult to troubleshoot without as oscilloscope - the kernel SPI driver does the heavy lifting and as long as I set the speed right and frame the data right it should just work.

From memory setting the speed too low would give me white and too high would give me black. I never had a random 1st led.

Are you sure you're on the right pin for SPI MOSI ?

Wolph · 7. Juli 2016

I'll test with a different header to be sure but I'm fairly certain it's connected properly. I'm using the Adafruit Prototyping Pi shield which makes it quite difficult to pick the wrong connection

https://www.adafruit.com/product/801

Unfortunately I don't have a scope to check... perhaps I should just order one as I've missed it quite often

Wolph · 9. Juli 2016

I'm thinking of buying this little device to check: https://www.saleae.com/

I've triple checked the wiring so I'm certain that's not the problem. Right now I'm actually thinking the SPI part of my Pi might be fried due to all my messing around.

penfold42 · 9. Juli 2016

Just got mine working.

Fresh raspbian install,
git clone from Hyperion.ng
compiled on the pi1 (I forgot how slow they are!)

i have a 60 led ring attached an the default config with only 46 leds defined.
Heres my device section of the config.
"device" :
{
"name" : "MyHyperionConfig",
"type" : "ws2812spi",
"output" : "/dev/spidev0.0",
// "rate" : 1000000,
"colorOrder" : "grb"
},

What do you get on the console from hyperiond /etc/hyperion/hyperion.config.json ?
(well, with _your_ config patch)

As for the wiring, the Pi and my led strip are powered by the same 50A 5V supply so I only need a single wire from MOSI to the led strip input signal

Wolph · 12. Juli 2016

I think I may have simply fried something on this Pi along the way. It's an old one anyhow so I've ordered a new pi to test.

Code

Hyperion Ambilight Deamon (710)
    Version   : V1.03.0 (GitHub-b8f7642/c5d5f2d-1465599599
    Build Time: Jun 11 2016 01:39:39
INFO: Selected configuration file: /etc/hyperion/hyperion.config.json.ws281x_spi
HYPERION INFO: ColorTransform 'default' => [0; 49]
HYPERION INFO: ColorCorrection 'default' => [0; 49]
HYPERION INFO: ColorAdjustment 'default' => [0; 49]
LEDDEVICE INFO: configuration:
{
    "colorOrder" : "grb",
    "name" : "MyHyperionConfig",
    "output" : "/dev/spidev0.0",
    "type" : "ws2812spi"
}


INFO: Creating linear smoothing
HYPERION (CS) INFO: Created linear-smoothing(interval_ms=50;settlingTime_ms=200;updateDelay=0
EFFECTENGINE INFO: 27 effects loaded from directory /usr/share/hyperion/effects
EFFECTENGINE INFO: Initializing Python interpreter
INFO: Hyperion started and initialised
INFO: Boot sequence 'Rainbow swirl' EFFECTENGINE INFO: run effect Rainbow swirl on channel 0
BLACKBORDER INFO: threshold set to 0 (0)
BLACKBORDER INFO: mode:default
started
INFO: Json server created and started on port 19444
INFO: Proto server created and started on port 19445
EFFECTENGINE INFO: effect finished

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penfold42 · 12. Juli 2016

You could try the SPI loop back test.

Grab spitest.c from a Google search and then hook a wire from MOSI to MISO

Wolph · 12. Juli 2016

Ah, thanks These are my first ventures with Pi GPIO... so far I've only used arduino's and custom eeproms to control electronics so it's a bit of a slow start.

Anyway... I've tried the loopback test and it indeed confirms that the Pi is at least partially dead. No useful output whatsoever from the SPI device.

penfold42 · 13. Juli 2016

Bummer - there's always PWM or USB arduino

penfold42 · 18. Juli 2016

I've added sk6812rgbw-spi support in Hyperion-ng

Wolph · 30. August 2016

I have everything set up on a Pi2 now and it appears to be working

The only problem I have right now is that it appears to be limited to 341 leds. Since leds * colours per led * spi bytes per colour = 341 * 3 * 4 = 4092 I'm guessing there is some 4k limit somewhere in the SPI code but I haven't been able to find it yet.

Do you have any idea @penfold42 ?

Wolph · 30. August 2016

Nevermind, I found it

The Raspberry Pi SPI buffer is set to 4k by default: http://stackoverflow.com/quest…i-buffer-size-in-raspbian

penfold42 · 31. August 2016

Good find !

Have you tested it with newer kernels that use the DMA driver by default ?

316 was the max I could test with - a 16x16 matrix + 60 led ring

Wolph · 31. August 2016

Not sure if this kernel has the DMA driver by default but I'm running this one: Linux raspberrypi 4.4.19-v7+ #906 SMP Tue Aug 23 15:53:06 BST 2016 armv7l GNU/Linux

Seems pretty recent

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