HOW MANY NEOPIXEL ON MB 6HC

Gianluca

I can't get more than 60 LEDs to light up on a neopixel RGB strip.
They are connected to a MB 6HC on the dedicated DOTSTAR port.
I have the latest firmware available (3.5.0.rc1)
It seemed to me that in the latest firmware the possible number was much higher...

droftarts

@Gianluca how are you powering the LEDs? From the 6HC, or an external 5V supply? What LEDs are you using? If you’re powering them from the 6HC, there’s a limit to the current the on board regulator can supply.

See https://docs.duet3d.com/en/User_manual/Connecting_hardware/IO_Neopixel_DotStar

Caution! LED strips can draw a considerable amount of power, usually up to 60mA per LED (for RGBW Neopixel LEDs, up to 80mA per LED). If you are powering the LED strip from the Duet, make sure that the Duet is able to supply sufficient current (maximum 0.8A total external load on +5V for MB6HC version 1.02 or later, 3A total for other MB6HC/MB6XD boards).

Ian

Gianluca

@droftarts
Yes, I am powering the LEDs via the motherboard, without external power. I know the limits of my 1.01B, in fact I apply a power only of P5 on 255...
Unfortunately, however, I turn on LED 58, 59, 60 and then the subsequent LEDs do not light up.
I see from the link you posted that the limit is 320 RGB LEDs...
But why can't I turn on more than 6 LEDs?

gloomyandy

@Gianluca 60 is the default max number of pixels, if you want to use more you need to specify that number using the U parameter to the M950 command when you define the pin etc. for the string. See: https://docs.duet3d.com/en/User_manual/Reference/Gcodes#m950-create-heater-fan-spindle-or-gpioservo-pin

Gianluca

@gloomyandy
Thank you! I missed the "U" parameter... all solved!

droftarts

@gloomyandy Thanks, I'll add this to the documentation, as we don't seem to mention this anywhere!

Ian

gloomyandy

@droftarts New to 3.5 I think....