Nordic Semiconductor is a norwegian electronics company making integrated circuits, mainly with Bluetooth Low Energy (BLE).
nRF5 is a series of ICs at the moment there are two main versions nRF51 and nRF52
Her vil det komme en beskrivelse av hvordan man setter opp toolchain for å jobbe med chiper fra Nordic semiconductor
There is a pretty good guides at Nordic's DevZone found here. [1] and [2]
And if you don't like Keil, you can use Segger embedded studio. Or an even better option is to use Eclipse see Eclipse Configuration
men i all hovedsak det man trenger for å komme igang er "Keil uVision"(IDE), Comandline tools, software Developement Kit (SDK). In addition a phone or a dongle will be usefull to check the connection.
Take a look here [3] for more information.
Eclipse and GNU ARM toolchain. [4] see also Eclipse Configuration.