This commit adds support for NRF52 TWI Master mode and slightly extends
existing I2C API. This is a breaking change, while mode selection needs to be
done during enabling I2C. There is one additional breaking change done because:
1) Unicore MX API design was PITA for writes
2) It is incompatible with EasyDMA
I strongly apologize to all two users who might be affected by this change.
* merged: nrf tree from unicore-mx
* fixed: small changes to make merged code play with rest of locm3 again
* added: linker script generator defines for nRF51/52 stubs
* added: doxygen support
This removes code and changes names and styles where relevant to be more
inline with normal libopencm3.
NRF52x library is built for hardfloat, M4F by default. The M4 no float
variants are less common, and if needed, the library can be built
manually for those variants. Unless some very common boards show up
using those parts, we don't need an extra library build.
Reviewed-by: Karl Palsson <karlp@tweak.net.au>
Tested-by: Karl Palsson <karlp@tweak.net.au>
Eduard Drusa