Some timing sensitive operations like PWM are possible on the old Pi by making the DMA controller directly transfer data from hardware PWM to GPIO without using any CPU cycles.
Frameworks like pigpio and servoblaster use that trick, but the standard gpio python module which doesn't use DMA has more mindshare, probably due to its simplicity.
There is an implementation of RTlinux for the RPi from the Navio guys [1], but I'm not sure if it's compatible with RPi2.
Frameworks like pigpio and servoblaster use that trick, but the standard gpio python module which doesn't use DMA has more mindshare, probably due to its simplicity.
There is an implementation of RTlinux for the RPi from the Navio guys [1], but I'm not sure if it's compatible with RPi2.
[1]: http://www.emlid.com/new-raspbian-with-real-time-kernel-jan-...