Sound question

We have an application that plays tones of frequencies ranging from
150 to 700 Hz. This application used ioctl() with /dev/fm under
QNX 4.25. I have not been able to find anything similar under
Neutrino. I am accessing a sound blaster compatible device,
currently under 6.1a but will be moving to 6.2 as soon as some
other issues get resolved. Does anyone know what the replacement
for /dev/fm is for Neutrino?

Any help would be greatly appreciated.

regards,
Tom

Thomas Emberson <temberson@softwareremodeling.com> wrote:

We have an application that plays tones of frequencies ranging from
150 to 700 Hz. This application used ioctl() with /dev/fm under
QNX 4.25. I have not been able to find anything similar under
Neutrino. I am accessing a sound blaster compatible device,
currently under 6.1a but will be moving to 6.2 as soon as some
other issues get resolved. Does anyone know what the replacement
for /dev/fm is for Neutrino?

Any help would be greatly appreciated.

If all you’re doing is playing sine waves, I’d suggest generating
them yourself directly into the D/A port. It’s not rocket science
but for a rather large fee :slight_smile: :slight_smile:

Basically, I’d create a sine array and precompute your sine
values into it, and then step through the sine array at some
fixed (precomputed) offset looping around. Done.

And, if it’s not sine waves, precompute something else into an array.

Cheers,
-RK


Robert Krten, PARSE Software Devices +1 613 599 8316.
Realtime Systems Architecture, Books, Video-based and Instructor-led
Training and Consulting at www.parse.com.
Email my initials at parse dot com.