[fpc-pascal] USB Human Interface Devices

[Marc Santhoff]

On Mon, 2019-08-19 at 04:24 -0400, James Richters wrote:
> I've been reading about libusb here:
> https://www.cs.unm.edu/~hjelmn/libusb_hotplug_api/group__syncio.html
>
> some things I just don't really understand, I'm hoping someone can explain:

I can't help with the details, but these sites are very informative,
especially the first one is nicely readable, the other has lots of details:

http://www.usbmadesimple.co.uk/index.html
https://www.beyondlogic.org/usbnutshell/usb1.shtml


> The wValue, wIndex and wLength fields values should be given in host-endian
> byte order.
> What does host-endian byte order mean??
>
> wLength
> the length field for the setup packet. The data buffer should be at least
> this size.
>
> What is this length supposed to be?  I've been using the length of the data
> I'm trying to send... so trying to send 8 bytes, I made it 8... but maybe
> it's wanting some other length?
>
> It seems to me that there would be little point in asking for this value if
> it was always just the length of the data field because the function could
> just get len(data) on it's own, so why bother passing something so obvious
> as a parameter...  this leads me to wonder if this length needs to be
> something else?
>
> James
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--
Marc Santhoff <M.Santhoff at web.de>