DotStar on Duet Wifi 2

[krohelm]

FIRMWARE_NAME: RepRapFirmware for Duet 2 WiFi/Ethernet FIRMWARE_VERSION: 3.4.0 ELECTRONICS: Duet WiFi 1.02 or later + DueX2 FIRMWARE_DATE: 2022-03-15 18:58:33

I'm trying to connect a DotStar strip to a Duet2 as documented here for neopixels: https://docs.duet3d.com/en/User_manual/Connecting_hardware/IO_Neopixel_DotStar

When sending M150 X0 P255 S20 I receive Error: M150: Unsupported LED strip type.

I have an external 5v PSU and have been historically driving these LEDs via a CircuitPython m4 but I'm trying to simplify the wiring and maintenance burden of my printer. Is there any way we can get DotStar allowed on Duet2?

[dc42]

@krohelm it's only Duet 3 MB6HC that supports both Dotstar and Neopixels. On other boards only Neopixels are supported. It would be possible to support Dotstar on Duet WiFi but users seem to prefer NeoPixels anyway.

[krohelm]

@dc42 Thanks for the reply - Dotstars have a pleasing non-flickering warm glow that is easy on my eyes . I have wired my printer with these for the last 2 years & they're awesome.

Looks like SUPPORT_BITBANG_NEOPIXEL is the only path for DUET_NG which I'm guessing aliases duet wifi based on other usages. The rest are SUPPORT_DMA_* (exception being PCCB_10 which I'm not sure I know what it is). I guess the Wifi only supports bitbang? These preprocessor definitions are dense & I'm not quite sure yet what needs to happen to add neopixel bitbang for DUET_NG!

[dc42]

@krohelm to support Dotstar in bit-bang mode you would first need to define which additional pin to use, since Dotstar needs 2 pins instead of just one. Then it's just a matter of using bit-banged SPI to send the data.

Caution, RRF3.4 uses almost all the available flash memory on Duet 2. Adding this support will probably push it over the limit unless something else is removed. In RRF3.5 I have already removed support for M667 to make a little more space available.