Hi, I've worked on an external that uses tv_usec for sending gpio pulses with a period under 1ms, it begin to work with no segfaults and low cpu process with the help of stallman's pthread library, it's not ready yet for sharing, maybe it's possible to send fast rate bangs like this? I would enjoy to see such attempts in other externals, good luck...
Colet Patrice
PS: it's really hard to believe that it's possible to go under 1us!