On May 24, 2007, at 6:39 PM, Marc R.J. Brevoort wrote: > On Thu, 24 May 2007, matthiasm wrote: > >> Have you though about realtime operating systems? None of the others >> will guarantee you a resolution of 1/1000th of a second. > > Actually the idea is to output MIDI notes alongside a JACK audio > stream- > specifically on Ubuntu Studio (assuming the kernel with realtime > patches). >
Ah, in this particular case, I may be able to help you. You can convince the audio hardware to trigger a hardware based interrupt inside you machine as soon as a given number of samples have been sent to the audio device. You can then use this interrupt to trigger the serial port - also pretty much directly in hardware, to immediatly send you Midi code. Since the interrupt will happen in superviser mode on a hardware level, you will not be interrupted by any user tasks. Access time to the serial port is also minimal, so you could do all that in a single go. Of course there is no great solution without a serious drawback ;-) . You will have to do all this from within the kernel drivers. You probably have to dig deep into the various sound card drivers out there and the serial port drivers as well. The solution however would be zero cost (no hardware) and very likely be right on the sample. 48kHz is not much fo machines that run 2 mio. instructions per second... . ---- http://robowerk.com/ _______________________________________________ fltk mailing list [email protected] http://lists.easysw.com/mailman/listinfo/fltk
