Accessing a USB device from Perl, part 3.

For the March meeting, Paul Archer lead a further session on the LibUSB/Delcom VSI project. During this presentation, we experimented with controlling two of the Delcom devices on one computer. None of the current prototyping code supports multiple devices with the same vendor and product id, so Paul solved the problem by

  1. plugging in one device
  2. programming it to flash all three colors
  3. plugging in the other device
  4. programming it to flash all three colors

We were also able to get the serial numbers from the two devices to verify show that we were looking at two different devices. There was some talk of changes to the libraries to allow us to talk to two devices at a time without plugging them in separately.

Paul explained the use of the Inline::init function for allow us to keep the C code in the __DATA__ section while still building a module. (It's in the Inline::C cookbook documentation, I just didn't read far enough.)

We also decided that this project had passed beyond the point where it makes an interesting presentation. There is still quite a bit of cleanup and some more functionality to implement. But none of that makes for an interesting presentation. Maybe we can have another quick wrapup when the project is complete.

Any further information about the project will be added to the project page: Delcom VSI/LibUSB Project.