Assorted links and notes for connecting an Orange PI (allwinner H2) to WS2812 lights.
- SPI Driver support for H2/3: https://forum.armbian.com/topic/840-h3-spi/page/2/
- H2 data sheet: http://wiki.friendlyarm.com/wiki/images/0/08/Allwinner_H2%2B_Datasheet_V1.2.pdf
- Half-duplex SPI/DMA discussion: https://forum.armbian.com/topic/1881-spi-with-dma-tx-only-doesnt-work/