From: bob 295 <icanprogram@29...> - 2012-03-21 13:32:59
I've been working with a Phidgets SBC board trying to teach myself USB and
libusb 1.0. (The current implementation which comes with the Phidgets
board is based on libusb 0.1)
My most recent attempt was a modification of the dpfp.c example which comes
with the libusb tarball. I vectored this at the Phidgets onboard 8/8/8
Interface Kit (interrupt) endpoint and added the poll() call to multiplex on
the USB file descriptors.
The code works somewhat as expected. I'm curious about a couple of things
surrounding the poll() call.
1) the delay interval of the poll() is 7ms, whereas the period between
interrupt callbacks is the expected 8ms. If I take the poll() out and
simply block on the libusb_handle_events() call my period is 8ms.
2) the poll() revent comes back with the POLLOUT (0x4) bit set which
indicates that "writing will now not block". I would have expected a
Thanks in advance for your help.