It uses the SPI0.0 interface
Pin#24 GPIO08 CE0 connects to CS
pin#19 GPIO10 MOSI connects to DIN
pin#21 GPIO09 MISO unconnected
pin#23 GPIO11 CLK connects to CLK
pin#20 GND connects to GN
pin#17 3.3V connects to VCC
Use https://github.com/rm-hull/luma.led_matrix with https://github.com/rm-hull/luma.core and https://github.com/rm-hull/luma.examples to drive ...
Alright, found a solution:
In spi.py I needed to change:
self._spi.writebytes([x for x in buf[start:end]])
as apparently the 4k limit is baked into spidev where the dotstar library is concerned.
Sorry it's not a complete answer, but my experience so far
using the Python3 spidev library,
I can open /dev/spidev0.0 or /dev/spidev0.1,
I can set the clock speed (noting that this is not a precise frequency, but something like nearest power of two)
I can write data, via Python or directly with echo foo > /dev/spidev0.$N
It comes out on BCM10, BCM11.