Objective Development Forums 2013-11-29T21:33:04+02:00 https://forums.obdev.at/app.php/feed/topic/8756 2013-11-29T21:33:04+02:00 2013-11-29T21:33:04+02:00 https://forums.obdev.at/viewtopic.php?t=8756&p=26270#p26270 <![CDATA[libusb and linux]]> I have little ADC working in windows. Now I like to port to linux (raspberry/beaglebone).
ADC act as HID. The working solution is writen in basic. After oppening USB (to get handle) I just repeated read like this

Code: 

declare function HidD_GetFeature lib "hid.dll" alias "HidD_GetFeature" (hnd As integer,buf As integer,len As integer) As Integer
HidD_GetFeature(HidHandle,buffer,9)


Now for linux I tried python and libusb. After twigling with permissions (dont need to be sudo any more) I can find and open interface based on name, but cant got any data from usb. Any idea?

The as short as possible python test. I tryed many values for request_type and request, but without success.

Code: 

import usb1

#Try to open my stick - no error checking at all
context = usb1.USBContext()
for device in context.getDeviceList(skip_on_error=True):
    if device.getProduct()=='IsolADC':
        devh=device.open()
        
print devh  #just print descriptor to see

#now try to get 8 bytes from control point
request_type=0# (1<<5) #HID CLASS
request=0 #1 #GET REPORT
value=0
index=0
length=8

tmp= devh.controlRead(request_type, request, value, index, length,0)
print len(tmp)
print '>',tmp

Statistics: Posted by eslavko — Fri Nov 29, 2013 9:33 pm

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