[libhid-discuss] timeout on interrupt read

Peter Stuge peter at stuge.se
Fri Feb 25 17:35:43 UTC 2011


Tarmo Johannes wrote:
> My task is to use a digital USB-controller (
> Redlab 1024LS
> http://www.meilhaus.de/index.php?id=26&user_produkte%5BPR%5D=90&L=1&cHash=f866b18d24

A perfect example of a product is abusing HID, maybe because of lack
of understanding of USB in the organization. It makes me mad. :(


> ) to read state of simple switches and use the information for
> sound synthesis at the end. 

Your project would be significantly easier if you could work with a
USB device that does not force all the HID BS on you.


> After some search libhid looks very promising!

Suggest looking at HIDAPI from Signal 11 if you need to speak raw HID.


> Does Endpoit OUT means get the data out FROM device or send them
> out TO deivce?

USB is host centric. OUT means to the device.


> and experimented also with different packet lengths (1 and 3
> instead of 8) but the result was always

You need to know what the device expects, in order to successfully
communicate with it.


> I would be most happy if you could help me further!

Is it at all possible for you to switch hardware? I would recommend
the Olimex LPC-P1343 development board instead, which I've made a
very simple example for. http://stuge.se/lpc-p1343_buttons.tar.bz2


//Peter



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