Tutorials?

https://www.tamasbondar.info/tech/compiling-for-nRF51822-with-make-and-gcc-on-linux

https://devzone.nordicsemi.com/question/70314/program-bluetooth-for-nrf51822-yunjia-board-with-stlink-v2/

Toolchain?

https://devzone.nordicsemi.com/question/5152/nrf51822-over-the-air-bootloader-with-gcc/ http://electronut.in/nrf51-adc-test/

ws2812 driving

https://webcache.googleusercontent.com/search?q=cache:kCZ5oZaW_JsJ:https://productize.be/driving-ws2812-programmable-rgb-leds-using-hardware-spi/+&cd=3&hl=cs&ct=clnk&gl=cz&client=ubuntu