pyusb-users — PyUSB users mailing list discussion

[pyusb-users] Still more problems with PyUSB

[Gerry <gb...@ge...>]

Now when I try to run my app I get the following error messages:

     d1 = device.read(endpoint.bEndpointAddress, endpoint.wMaxPacketSize)
   File "/usr/local/lib/python2.7/dist-packages/usb/core.py", line 918, 
in read
     self.__get_timeout(timeout))
   File "/usr/local/lib/python2.7/dist-packages/usb/backend/libusb0.py", 
line 507, in intr_read
     timeout)
   File "/usr/local/lib/python2.7/dist-packages/usb/backend/libusb0.py", 
line 562, in __read
     timeout
   File "/usr/local/lib/python2.7/dist-packages/usb/backend/libusb0.py", 
line 380, in _check
     raise USBError(errmsg, ret)
usb.core.USBError: [Errno None] Connection timed out"

I am using "virtualenv" which was set up with Python 3.2.3 yet the 
errors are occurring in Python 2.7 PyUSB core and lisbusb0 even though I 
have specified to include "backend/libusb1"

Any and all help will be greatly appreciated to fix these PyUSB problems.

Thanks,

Gerald

Re: [pyusb-users] Help with writing a driver for USB HID device.

[Wander L. C. <wan...@gm...>]

2014-11-13 12:14 GMT-02:00 Anatoly Verkhovsky <an...@gm...>:
> Hi,
>

Hi, sorry for the delay, but I was out most of the month.

> I'm writing a driver for a device.  It was originally using MDB ICP, but now
> it ships with a USB to MDB bridge, why they have chosen to do it as HID
> rather then USB Serial i have no idea.  So behind the usb there is a simple
> serial protocol.
>

[snip]

> Here is the gist of my code:
>
> dev = usb.core.find(idVendor=0x155d, idProduct=0x0002)
> # check and remove kernel driver
> dev.set_configuration()
> dev.reset()

iirc, reset is problematic in Windows (maybe a should log a warning
for this), what if you remove it?

> # bmRequestType, bRequest are taken from SnoopyPro trace.
> res = dev.ctrl_transfer(0x22, 0x9, 0, 0, [0x02, 0x85, 0x0a], 1000)

This seems to be a class request, so it is a HID class request?

> data = dev.read(0x82, 32, timeout=10000)
>
> ctrl_transfer fails with USBError(32, 'Pipe error') and
> after couple of retries : USBError(19, 'No such device (it may have been
> disconnected)')

In general, this kind of errors in Windows is due to the reset call.

> i have also tried the whole byte string from the capture
>
> res = dev.ctrl_transfer(0x22, 0x9, 0, 0, [0x03, 0x02, 0x85, 0x0a, 0x05,
> 0x14, 0xff, 0xff], 1000)
>
> to same effect.
>
> So what am i missing?
> Why is the trace saying that host to device message is using function 0x1b
> (Class interface) and device to host is using function 0x08 (control
> transfer), shouldn't it be the other way around?
>
> thanks,
> Anatoli
>
>
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>



-- 
Best Regards,
Wander Lairson Costa

Re: [pyusb-users] Detect device on Mac

[Steven M. <smi...@gm...>]

> On Dec 26, 2014, at 8:41 PM, Wander Lairson Costa <wan...@gm...> wrote:
> 
> 2014-11-17 7:56 GMT-02:00 Oci Ocean <oci...@gm...>:
>> Hallo together,
>> 
> 
> Hi, sorry for the delay.
> 
>> I have a problem  detecting my ir-reciever on Mac 10.8.
>> The ir-reciever is noticed by the oporating system and i can control
>> iTunes with a remote control but:
>> 
>> device = usb.core.find(find_all=True)
>> 
>> just finds USB-Mouse and Keyboard.
>> 
>> Where is my mistake or what can i do to have success?
>> 
> 
> So, I am not a Mac guy, does Mac have a lsusb like tool? Does your
> device appear there?
> 
The USB view under Hardware in the “System Information” app.

/Applications/Utilities/System Information

There are developer tools that provide some more information.
https://developer.apple.com/hardwaredrivers/ <https://developer.apple.com/hardwaredrivers/>

You have to register as a developer, and it should be available with the free developer account.  Although you probably don’t need these tools, it does include an optionaly logging USB kernel driver for OSX

> Best Regards,
> Wander Lairson Costa
> 
> ------------------------------------------------------------------------------
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Re: [pyusb-users] Detect device on Mac

[Wander L. C. <wan...@gm...>]

2014-11-17 7:56 GMT-02:00 Oci Ocean <oci...@gm...>:
> Hallo together,
>

Hi, sorry for the delay.

> I have a problem  detecting my ir-reciever on Mac 10.8.
> The ir-reciever is noticed by the oporating system and i can control
> iTunes with a remote control but:
>
> device = usb.core.find(find_all=True)
>
> just finds USB-Mouse and Keyboard.
>
> Where is my mistake or what can i do to have success?
>

So, I am not a Mac guy, does Mac have a lsusb like tool? Does your
device appear there?

Best Regards,
Wander Lairson Costa

[pyusb-users] Out for the rest of the month

[Wander L. C. <wan...@gm...>]

Hi,

I just would like to let you know that I will be out for vacation for
the rest of the month, so support requests and PR will take some time
to request answered.

Merry Christmas!

-- 
Best Regards,
Wander Lairson Costa

[pyusb-users] Unexpected delay when writing to a USB HID interrupt endpoint

[Jeff R. <je...@ro...>]

Darn, I forgot a helpful subject line. Sorry about that. Fixed now...though
that probably means I broke the thread structure.

I was able to re-test on a laptop running an older version of Linux Mint
natively (no VM), and after a few compatibility tweaks, I got it to
communicate correctly AND there is no weird delay anymore! I believe the
issue may be specific to the VM, although I am really unsure why, and would
love any insight anyone might have. I also need to do some more testing on
a different machine with the latest Ubuntu, so that I can more confidently
point at the VM environment as the cause rather than something else.

In case anyone is interested, I've pushed the relevant code up to a Github
repo:

https://github.com/jrowberg/keyglove/blob/master/host/python/kglib.py#L335

If I learn anything more, I'll be sure to follow up.

--Jeff


On Sat, Dec 6, 2014 at 12:55 AM, Jeff Rowberg <je...@ro...> wrote:

Hello PyUSB community!
>
> I'm trying to solve a raw HID write delay problem when using PyUSB 1.0.0b2
> with Python 2.7 in an Ubuntu 14.10 Linux environment, actually running
> inside a VMware Player virtual machine on a Windows 8.1 64-bit desktop. I'm
> communicating from the Python script to a Teensy++ configured in Raw HID
> mode. I have been able to make this work perfectly in Windows using
> PyWinUSB, and using the Teensy++ manufacturer's own RawHID C demo code, and
> *almost* in Linux with PyUSB. In fact, I even get the data moving back and
> forth over the IN and OUT interrupt endpoints, intact and in order.
>
> The problem is that there is a very measurable delay (usually between
> 200ms and 500ms, varying) whenever I try to use the .write() method to send
> data to the device. I receive it instantly whenever anything new comes in;
> I've narrowed down the delay very specifically to the single line that
> attempts to send data:
>
>     self.pyusb_endpoint_out.write(raw_packet)
>
> The "raw_packet" variable is an array of bytes. The data is delivered
> properly, and everything else works great on the device and in the response
> that comes back, so I know it's being interpreted correctly. It just takes
> way longer than it should.
>
> First, here's the string representation of the interface that I'm using:
>
>     INTERFACE 0: Human Interface Device ====================
>      bLength            :    0x9 (9 bytes)
>      bDescriptorType    :    0x4 Interface
>      bInterfaceNumber   :    0x0
>      bAlternateSetting  :    0x0
>      bNumEndpoints      :    0x2
>      bInterfaceClass    :    0x3 Human Interface Device
>      bInterfaceSubClass :    0x0
>      bInterfaceProtocol :    0x0
>      iInterface         :    0x2 Teensyduino RawHID
>       ENDPOINT 0x83: Interrupt IN ==========================
>        bLength          :    0x7 (7 bytes)
>        bDescriptorType  :    0x5 Endpoint
>        bEndpointAddress :   0x83 IN
>        bmAttributes     :    0x3 Interrupt
>        wMaxPacketSize   :   0x40 (64 bytes)
>        bInterval        :    0x1
>       ENDPOINT 0x4: Interrupt OUT ==========================
>        bLength          :    0x7 (7 bytes)
>        bDescriptorType  :    0x5 Endpoint
>        bEndpointAddress :    0x4 OUT
>        bmAttributes     :    0x3 Interrupt
>        wMaxPacketSize   :   0x40 (64 bytes)
>        bInterval        :    0x1
>
> I read data from 0x83 and send it out 0x4. Both are interrupt endpoints,
> so I would assume this should be pretty straightforward.
>
> The Python script is fairly complicated, so I won't post the whole thing
> here (though I will be happy to post it on Github if needed; that's where
> it will end up, but I was kinda hoping to actually make it work first).
> However, salient points about its functionality are these:
>
> 1. It's running in VM of Ubuntu 14.10, on a Win8 machine. I can try a
> non-VM Ubuntu environment, but it will take some time to arrange that.
>
> 2. The script starts a separate daemon thread which constantly tries to
> read from endpoint 0x83, timing out every second and retrying whenever
> there is no data available. This approach seems to work perfectly, but I'm
> wondering if it has some adverse effect on the ability to write data in a
> timely fashion. The thread runs in a single handler function that looks
> like this:
>
>     # handler for reading incoming raw HID packets via PyUSB (thread
> started in local connect() method)
>     def pyusb_read_handler(self):
>         while self.pyusb_endpoint_in != None and self.connected:
>             try:
>                 ret =
> self.devobj.read(self.pyusb_endpoint_in.bEndpointAddress,
> self.pyusb_endpoint_in.wMaxPacketSize)
>                 if len(ret) > 0 and ret[0] > 0:
>                     for b in ret[1:ret[0] + 1]:
>                         if self.kgapi.parse(b) == 0xC0:
>                             self.responses_pending =
> self.responses_pending - 1
>                             if self.responses_pending == 0:
>                                 self.on_api_idle()
>             except usb.core.USBError as e:
>                 if e.errno == 110:
>                     # PyUSB timeout, probably just no data
>                     sys.exc_clear()
>                 elif e.errno == 5 or e.errno == 19:
>                     # "Input/Output Error" or "No such device", this is
> serious
>                     self.on_unplugged()
>                     self.disconnect()
>                 else:
>                     raise KeygloveHIDError("PyUSB read thread error: %s" %
> e)
>
> 3. The packets being sent are 64 bytes in size. The trailing bytes beyond
> the important part of the data payload are padded to zeros to fill the
> whole size. I had originally tried without doing this (by accident, in
> fact), so the byte array I wrote was only perhaps 5-10 bytes long, and then
> realized that I'd forgotten to pad it. However, the same delay exists
> whether or not the bytes are zero-padded out to the full report size, so
> that isn't it.
>
> Given the above, is there ANY reason why there would be a 100+ millisecond
> seemingly arbitrary delay sending a 64-byte packet?
>
> --Jeff
>
>
>
> ------------------------------------------------------------------------------
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>
>

[pyusb-users] (no subject)

[Jeff R. <je...@ro...>]

Hello PyUSB community!

I'm trying to solve a raw HID write delay problem when using PyUSB 1.0.0b2
with Python 2.7 in an Ubuntu 14.10 Linux environment, actually running
inside a VMware Player virtual machine on a Windows 8.1 64-bit desktop. I'm
communicating from the Python script to a Teensy++ configured in Raw HID
mode. I have been able to make this work perfectly in Windows using
PyWinUSB, and using the Teensy++ manufacturer's own RawHID C demo code, and
*almost* in Linux with PyUSB. In fact, I even get the data moving back and
forth over the IN and OUT interrupt endpoints, intact and in order.

The problem is that there is a very measurable delay (usually between 200ms
and 500ms, varying) whenever I try to use the .write() method to send data
to the device. I receive it instantly whenever anything new comes in; I've
narrowed down the delay very specifically to the single line that attempts
to send data:

    self.pyusb_endpoint_out.write(raw_packet)

The "raw_packet" variable is an array of bytes. The data is delivered
properly, and everything else works great on the device and in the response
that comes back, so I know it's being interpreted correctly. It just takes
way longer than it should.

First, here's the string representation of the interface that I'm using:

    INTERFACE 0: Human Interface Device ====================
     bLength            :    0x9 (9 bytes)
     bDescriptorType    :    0x4 Interface
     bInterfaceNumber   :    0x0
     bAlternateSetting  :    0x0
     bNumEndpoints      :    0x2
     bInterfaceClass    :    0x3 Human Interface Device
     bInterfaceSubClass :    0x0
     bInterfaceProtocol :    0x0
     iInterface         :    0x2 Teensyduino RawHID
      ENDPOINT 0x83: Interrupt IN ==========================
       bLength          :    0x7 (7 bytes)
       bDescriptorType  :    0x5 Endpoint
       bEndpointAddress :   0x83 IN
       bmAttributes     :    0x3 Interrupt
       wMaxPacketSize   :   0x40 (64 bytes)
       bInterval        :    0x1
      ENDPOINT 0x4: Interrupt OUT ==========================
       bLength          :    0x7 (7 bytes)
       bDescriptorType  :    0x5 Endpoint
       bEndpointAddress :    0x4 OUT
       bmAttributes     :    0x3 Interrupt
       wMaxPacketSize   :   0x40 (64 bytes)
       bInterval        :    0x1

I read data from 0x83 and send it out 0x4. Both are interrupt endpoints, so
I would assume this should be pretty straightforward.

The Python script is fairly complicated, so I won't post the whole thing
here (though I will be happy to post it on Github if needed; that's where
it will end up, but I was kinda hoping to actually make it work first).
However, salient points about its functionality are these:

1. It's running in VM of Ubuntu 14.10, on a Win8 machine. I can try a
non-VM Ubuntu environment, but it will take some time to arrange that.

2. The script starts a separate daemon thread which constantly tries to
read from endpoint 0x83, timing out every second and retrying whenever
there is no data available. This approach seems to work perfectly, but I'm
wondering if it has some adverse effect on the ability to write data in a
timely fashion. The thread runs in a single handler function that looks
like this:

    # handler for reading incoming raw HID packets via PyUSB (thread
started in local connect() method)
    def pyusb_read_handler(self):
        while self.pyusb_endpoint_in != None and self.connected:
            try:
                ret =
self.devobj.read(self.pyusb_endpoint_in.bEndpointAddress,
self.pyusb_endpoint_in.wMaxPacketSize)
                if len(ret) > 0 and ret[0] > 0:
                    for b in ret[1:ret[0] + 1]:
                        if self.kgapi.parse(b) == 0xC0:
                            self.responses_pending = self.responses_pending
- 1
                            if self.responses_pending == 0:
                                self.on_api_idle()
            except usb.core.USBError as e:
                if e.errno == 110:
                    # PyUSB timeout, probably just no data
                    sys.exc_clear()
                elif e.errno == 5 or e.errno == 19:
                    # "Input/Output Error" or "No such device", this is
serious
                    self.on_unplugged()
                    self.disconnect()
                else:
                    raise KeygloveHIDError("PyUSB read thread error: %s" %
e)

3. The packets being sent are 64 bytes in size. The trailing bytes beyond
the important part of the data payload are padded to zeros to fill the
whole size. I had originally tried without doing this (by accident, in
fact), so the byte array I wrote was only perhaps 5-10 bytes long, and then
realized that I'd forgotten to pad it. However, the same delay exists
whether or not the bytes are zero-padded out to the full report size, so
that isn't it.

Given the above, is there ANY reason why there would be a 100+ millisecond
seemingly arbitrary delay sending a 64-byte packet?

--Jeff

Re: [pyusb-users] PyUSB on Intel Galileo Gen 2

[Wander L. C. <wan...@gm...>]

Hi,

Could you please run with the env var PYUSB_DEBUG=debug and post the logs?

2014-11-25 3:31 GMT-02:00 Setia Budi <boe...@gm...>:
> Actually, libusb is available on Yocto Linux:
>
> root@clanton:~# ls /lib/ | grep libusb
> libusb-0.1.so.4
> libusb-0.1.so.4.4.4
> libusb-1.0.so.0
> libusb-1.0.so.0.1.0
>
> But still, every time I call my script, I always have this error message
>
> Traceback (most recent call last):
>   File "pyru824.py", line 71, in <module>
>     RFID_READER = usb.core.find(idVendor=VENDOR_ID, idProduct=PRODUCT_ID)
>   File "/usr/lib/python2.7/site-packages/usb/core.py", line 1199, in find
>     raise ValueError('No backend available')
> ValueError: No backend available
>
> Kind regards,
> Budi
>
>
> On Tue, Nov 25, 2014 at 12:49 PM, Setia Budi <boe...@gm...> wrote:
>>
>> configure: error: in `/home/root/libusb-1.0.9':
>> configure: error: no acceptable C compiler found in $PATH
>>
>>
>> Need to get c compiler >.<
>>
>>
>>
>> On Tue, Nov 25, 2014 at 12:23 PM, Setia Budi <boe...@gm...> wrote:
>>>
>>> Thanks for the hint. I will try it now :)
>>>
>>> Kind regards,
>>> Budi
>>>
>>> On Tue, Nov 25, 2014 at 12:17 PM, Xiaofan Chen <xia...@gm...>
>>> wrote:
>>>>
>>>> On Tue, Nov 25, 2014 at 7:33 AM, Setia Budi <boe...@gm...>
>>>> wrote:
>>>> > Hi all,
>>>> > At the moment I am working with Intel Galileo Gen2 with Yocto Linux
>>>> > running
>>>> > on top of it. This micro PC is planned to replace some other micro PC
>>>> > for
>>>> > field experiment.
>>>> > I installed pyusb on it without any issue, however, once I run my
>>>> > script,
>>>> > which is using pyusb module, I found this error message:
>>>> >
>>>> > Traceback (most recent call last):
>>>> >   File "pyru824.py", line 71, in <module>
>>>> >     RFID_READER = usb.core.find(idVendor=VENDOR_ID,
>>>> > idProduct=PRODUCT_ID)
>>>> >   File "/usr/lib/python2.7/site-packages/usb/core.py", line 1199, in
>>>> > find
>>>> >     raise ValueError('No backend available')
>>>> > ValueError: No backend available
>>>> >
>>>> > I am just wondering whether anyone has a solution for this problem?
>>>> > Thank you :)
>>>>
>>>> Did you install libusb-1.0? For Linux it is better to install libusb-1.0
>>>> as the backend for pyusb. If your Linux distro does not provide
>>>> the package, then you need to build from source. But most
>>>> Linux distros provide libusb-1.0.
>>>>
>>>> Website: http://libusb.info/
>>>> Download: http://sourceforge.net/projects/libusb/
>>>>
>>>>
>>>> --
>>>> Xiaofan
>>>>
>>>>
>>>> ------------------------------------------------------------------------------
>>>> Download BIRT iHub F-Type - The Free Enterprise-Grade BIRT Server
>>>> from Actuate! Instantly Supercharge Your Business Reports and Dashboards
>>>> with Interactivity, Sharing, Native Excel Exports, App Integration &
>>>> more
>>>> Get technology previously reserved for billion-dollar corporations, FREE
>>>>
>>>> http://pubads.g.doubleclick.net/gampad/clk?id=157005751&iu=/4140/ostg.clktrk
>>>> _______________________________________________
>>>> pyusb-users mailing list
>>>> pyu...@li...
>>>> https://lists.sourceforge.net/lists/listinfo/pyusb-users
>>>
>>>
>>
>
>
> ------------------------------------------------------------------------------
> Download BIRT iHub F-Type - The Free Enterprise-Grade BIRT Server
> from Actuate! Instantly Supercharge Your Business Reports and Dashboards
> with Interactivity, Sharing, Native Excel Exports, App Integration & more
> Get technology previously reserved for billion-dollar corporations, FREE
> http://pubads.g.doubleclick.net/gampad/clk?id=157005751&iu=/4140/ostg.clktrk
> _______________________________________________
> pyusb-users mailing list
> pyu...@li...
> https://lists.sourceforge.net/lists/listinfo/pyusb-users
>



-- 
Best Regards,
Wander Lairson Costa

Re: [pyusb-users] PyUSB on Intel Galileo Gen 2

[Setia B. <boe...@gm...>]

Actually, libusb is available on Yocto Linux:

root@clanton:~# ls /lib/ | grep libusb
libusb-0.1.so.4
libusb-0.1.so.4.4.4
libusb-1.0.so.0
libusb-1.0.so.0.1.0

But still, every time I call my script, I always have this error message

Traceback (most recent call last):
  File "pyru824.py", line 71, in <module>
    RFID_READER = usb.core.find(idVendor=VENDOR_ID, idProduct=PRODUCT_ID)
  File "/usr/lib/python2.7/site-packages/usb/core.py", line 1199, in find
    raise ValueError('No backend available')
ValueError: No backend available

Kind regards,
Budi


On Tue, Nov 25, 2014 at 12:49 PM, Setia Budi <boe...@gm...> wrote:

> configure: error: in `/home/root/libusb-1.0.9':
> configure: error: no acceptable C compiler found in $PATH
>
>
> Need to get c compiler >.<
>
>
>
> On Tue, Nov 25, 2014 at 12:23 PM, Setia Budi <boe...@gm...> wrote:
>
>> Thanks for the hint. I will try it now :)
>>
>> Kind regards,
>> Budi
>>
>> On Tue, Nov 25, 2014 at 12:17 PM, Xiaofan Chen <xia...@gm...>
>> wrote:
>>
>>> On Tue, Nov 25, 2014 at 7:33 AM, Setia Budi <boe...@gm...>
>>> wrote:
>>> > Hi all,
>>> > At the moment I am working with Intel Galileo Gen2 with Yocto Linux
>>> running
>>> > on top of it. This micro PC is planned to replace some other micro PC
>>> for
>>> > field experiment.
>>> > I installed pyusb on it without any issue, however, once I run my
>>> script,
>>> > which is using pyusb module, I found this error message:
>>> >
>>> > Traceback (most recent call last):
>>> >   File "pyru824.py", line 71, in <module>
>>> >     RFID_READER = usb.core.find(idVendor=VENDOR_ID,
>>> idProduct=PRODUCT_ID)
>>> >   File "/usr/lib/python2.7/site-packages/usb/core.py", line 1199, in
>>> find
>>> >     raise ValueError('No backend available')
>>> > ValueError: No backend available
>>> >
>>> > I am just wondering whether anyone has a solution for this problem?
>>> > Thank you :)
>>>
>>> Did you install libusb-1.0? For Linux it is better to install libusb-1.0
>>> as the backend for pyusb. If your Linux distro does not provide
>>> the package, then you need to build from source. But most
>>> Linux distros provide libusb-1.0.
>>>
>>> Website: http://libusb.info/
>>> Download: http://sourceforge.net/projects/libusb/
>>>
>>>
>>> --
>>> Xiaofan
>>>
>>>
>>> ------------------------------------------------------------------------------
>>> Download BIRT iHub F-Type - The Free Enterprise-Grade BIRT Server
>>> from Actuate! Instantly Supercharge Your Business Reports and Dashboards
>>> with Interactivity, Sharing, Native Excel Exports, App Integration & more
>>> Get technology previously reserved for billion-dollar corporations, FREE
>>>
>>> http://pubads.g.doubleclick.net/gampad/clk?id=157005751&iu=/4140/ostg.clktrk
>>> _______________________________________________
>>> pyusb-users mailing list
>>> pyu...@li...
>>> https://lists.sourceforge.net/lists/listinfo/pyusb-users
>>>
>>
>>
>

Re: [pyusb-users] PyUSB on Intel Galileo Gen 2

[Setia B. <boe...@gm...>]

configure: error: in `/home/root/libusb-1.0.9':
configure: error: no acceptable C compiler found in $PATH


Need to get c compiler >.<



On Tue, Nov 25, 2014 at 12:23 PM, Setia Budi <boe...@gm...> wrote:

> Thanks for the hint. I will try it now :)
>
> Kind regards,
> Budi
>
> On Tue, Nov 25, 2014 at 12:17 PM, Xiaofan Chen <xia...@gm...> wrote:
>
>> On Tue, Nov 25, 2014 at 7:33 AM, Setia Budi <boe...@gm...> wrote:
>> > Hi all,
>> > At the moment I am working with Intel Galileo Gen2 with Yocto Linux
>> running
>> > on top of it. This micro PC is planned to replace some other micro PC
>> for
>> > field experiment.
>> > I installed pyusb on it without any issue, however, once I run my
>> script,
>> > which is using pyusb module, I found this error message:
>> >
>> > Traceback (most recent call last):
>> >   File "pyru824.py", line 71, in <module>
>> >     RFID_READER = usb.core.find(idVendor=VENDOR_ID,
>> idProduct=PRODUCT_ID)
>> >   File "/usr/lib/python2.7/site-packages/usb/core.py", line 1199, in
>> find
>> >     raise ValueError('No backend available')
>> > ValueError: No backend available
>> >
>> > I am just wondering whether anyone has a solution for this problem?
>> > Thank you :)
>>
>> Did you install libusb-1.0? For Linux it is better to install libusb-1.0
>> as the backend for pyusb. If your Linux distro does not provide
>> the package, then you need to build from source. But most
>> Linux distros provide libusb-1.0.
>>
>> Website: http://libusb.info/
>> Download: http://sourceforge.net/projects/libusb/
>>
>>
>> --
>> Xiaofan
>>
>>
>> ------------------------------------------------------------------------------
>> Download BIRT iHub F-Type - The Free Enterprise-Grade BIRT Server
>> from Actuate! Instantly Supercharge Your Business Reports and Dashboards
>> with Interactivity, Sharing, Native Excel Exports, App Integration & more
>> Get technology previously reserved for billion-dollar corporations, FREE
>>
>> http://pubads.g.doubleclick.net/gampad/clk?id=157005751&iu=/4140/ostg.clktrk
>> _______________________________________________
>> pyusb-users mailing list
>> pyu...@li...
>> https://lists.sourceforge.net/lists/listinfo/pyusb-users
>>
>
>

Re: [pyusb-users] Access Denied Error on Windows 7

[Xiaofan C. <xia...@gm...>]

On Tue, Nov 25, 2014 at 2:42 AM, Richard Bryan <ra...@lu...> wrote:
> Hi Wander,
>
> I ran with PYUSB_DEBUG=debug and encountered the error.  The log text when
> the error occurred is here:
>
> http://pastebin.com/kmqSrek9
>
> Its the pyusb debug log intermingled with my program's logging information
> as well.  The first "Access Denied" error occurs at line 1527.  There are
> also a bunch '[Errno 10060] Operation timed out' errors that occur leading
> up to the access denied error.  Just looking at the pyusb log messages
> around the time the errors are reported by my program, I didn't see anything
> that looked relevant...
>

You should probably ask in the libusb mailing list. Right now I can not
access your pastebin message but sometimes it is caused by the
device problem (device hangs and lost on the USB bus).

Please also make sure you are using libusb-1.0.19 which is the
latest release version.



-- 
Xiaofan

Re: [pyusb-users] PyUSB on Intel Galileo Gen 2

[Setia B. <boe...@gm...>]

Thanks for the hint. I will try it now :)

Kind regards,
Budi

On Tue, Nov 25, 2014 at 12:17 PM, Xiaofan Chen <xia...@gm...> wrote:

> On Tue, Nov 25, 2014 at 7:33 AM, Setia Budi <boe...@gm...> wrote:
> > Hi all,
> > At the moment I am working with Intel Galileo Gen2 with Yocto Linux
> running
> > on top of it. This micro PC is planned to replace some other micro PC for
> > field experiment.
> > I installed pyusb on it without any issue, however, once I run my script,
> > which is using pyusb module, I found this error message:
> >
> > Traceback (most recent call last):
> >   File "pyru824.py", line 71, in <module>
> >     RFID_READER = usb.core.find(idVendor=VENDOR_ID, idProduct=PRODUCT_ID)
> >   File "/usr/lib/python2.7/site-packages/usb/core.py", line 1199, in find
> >     raise ValueError('No backend available')
> > ValueError: No backend available
> >
> > I am just wondering whether anyone has a solution for this problem?
> > Thank you :)
>
> Did you install libusb-1.0? For Linux it is better to install libusb-1.0
> as the backend for pyusb. If your Linux distro does not provide
> the package, then you need to build from source. But most
> Linux distros provide libusb-1.0.
>
> Website: http://libusb.info/
> Download: http://sourceforge.net/projects/libusb/
>
>
> --
> Xiaofan
>
>
> ------------------------------------------------------------------------------
> Download BIRT iHub F-Type - The Free Enterprise-Grade BIRT Server
> from Actuate! Instantly Supercharge Your Business Reports and Dashboards
> with Interactivity, Sharing, Native Excel Exports, App Integration & more
> Get technology previously reserved for billion-dollar corporations, FREE
>
> http://pubads.g.doubleclick.net/gampad/clk?id=157005751&iu=/4140/ostg.clktrk
> _______________________________________________
> pyusb-users mailing list
> pyu...@li...
> https://lists.sourceforge.net/lists/listinfo/pyusb-users
>

Re: [pyusb-users] PyUSB on Intel Galileo Gen 2

[Xiaofan C. <xia...@gm...>]

On Tue, Nov 25, 2014 at 7:33 AM, Setia Budi <boe...@gm...> wrote:
> Hi all,
> At the moment I am working with Intel Galileo Gen2 with Yocto Linux running
> on top of it. This micro PC is planned to replace some other micro PC for
> field experiment.
> I installed pyusb on it without any issue, however, once I run my script,
> which is using pyusb module, I found this error message:
>
> Traceback (most recent call last):
>   File "pyru824.py", line 71, in <module>
>     RFID_READER = usb.core.find(idVendor=VENDOR_ID, idProduct=PRODUCT_ID)
>   File "/usr/lib/python2.7/site-packages/usb/core.py", line 1199, in find
>     raise ValueError('No backend available')
> ValueError: No backend available
>
> I am just wondering whether anyone has a solution for this problem?
> Thank you :)

Did you install libusb-1.0? For Linux it is better to install libusb-1.0
as the backend for pyusb. If your Linux distro does not provide
the package, then you need to build from source. But most
Linux distros provide libusb-1.0.

Website: http://libusb.info/
Download: http://sourceforge.net/projects/libusb/


-- 
Xiaofan

[pyusb-users] PyUSB on Intel Galileo Gen 2

[Setia B. <boe...@gm...>]

Hi all,
At the moment I am working with Intel Galileo Gen2 with Yocto Linux running
on top of it. This micro PC is planned to replace some other micro PC for
field experiment.
I installed pyusb on it without any issue, however, once I run my script,
which is using pyusb module, I found this error message:

Traceback (most recent call last):
  File "pyru824.py", line 71, in <module>
    RFID_READER = usb.core.find(idVendor=VENDOR_ID, idProduct=PRODUCT_ID)
  File "/usr/lib/python2.7/site-packages/usb/core.py", line 1199, in find
    raise ValueError('No backend available')
ValueError: No backend available

I am just wondering whether anyone has a solution for this problem?
Thank you :)

Kind regards,
Budi

Re: [pyusb-users] Access Denied Error on Windows 7

[Richard B. <ra...@lu...>]

Hi Wander,

I ran with PYUSB_DEBUG=debug and encountered the error.  The log text when
the error occurred is here:

http://pastebin.com/kmqSrek9

Its the pyusb debug log intermingled with my program's logging information
as well.  The first "Access Denied" error occurs at line 1527.  There are
also a bunch '[Errno 10060] Operation timed out' errors that occur leading
up to the access denied error.  Just looking at the pyusb log messages
around the time the errors are reported by my program, I didn't see
anything that looked relevant...

Richard


Date: Thu, 13 Nov 2014 09:54:31 -0200
From: Wander Lairson Costa <wan...@gm...>
Subject: Re: [pyusb-users] Access Denied Error on Windows 7
To: pyusb-users <pyu...@li...>
Message-ID:
        <CAFsSK4ZsCYbR8eQETrDrcU0QU+f_
05bKShpWgQdE6SA5K=50...@ma...>
Content-Type: text/plain; charset=UTF-8

2014-11-11 15:22 GMT-02:00 Richard Bryan <ra...@lu...>:
> I'm frequently running into an "Access Denied (insufficient permissions)"
> errors on Windows 7 (with libusb1 backend) during long-running usb
sessions
> with a device.  When this happens, I call reset() and dispose_resources()
on
> the usb handle and then attempt to reenumerate it using usb.core.find(),
but
> the Access Denied error keeps occurring until I unplug and replug the
> device.  Restarting the program alone doesnt fix it.
>

iirc, libusb reset operation is problematic under Windows, so better
to avoid it.

> I have a multithreaded program, but interaction with pyusb is only ever
done
> in the same, single thread.
>

This should not cause problems...

> Anyone have any ideas what's going on?  Or is this something I should ask
> the libusb list about?
>

Could you please run you program with the environment variable
PYUSB_DEBUG=debug defined and report the logs?

> Richard
>
>
------------------------------------------------------------------------------
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> Monitor 10 servers for $9/Month.
> Get alerted through email, SMS, voice calls or mobile push notifications.
> Take corrective actions from your mobile device.
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http://pubads.g.doubleclick.net/gampad/clk?id=154624111&iu=/4140/ostg.clktrk
> _______________________________________________
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> pyu...@li...
> https://lists.sourceforge.net/lists/listinfo/pyusb-users
>



--
Best Regards,
Wander Lairson Costa

[pyusb-users] Detect device on Mac

[Oci O. <oci...@gm...>]

Hallo together,

I have a problem  detecting my ir-reciever on Mac 10.8.
The ir-reciever is noticed by the oporating system and i can control 
iTunes with a remote control but:

device = usb.core.find(find_all=True)

just finds USB-Mouse and Keyboard.

Where is my mistake or what can i do to have success?

Kind regards
Oci

Re: [pyusb-users] Access Denied Error on Windows 7

[Xiaofan C. <xia...@gm...>]

On Wed, Nov 12, 2014 at 1:22 AM, Richard Bryan <ra...@lu...> wrote:
> I'm frequently running into an "Access Denied (insufficient permissions)"
> errors on Windows 7 (with libusb1 backend) during long-running usb sessions
> with a device.  When this happens, I call reset() and dispose_resources() on
> the usb handle and then attempt to reenumerate it using usb.core.find(), but
> the Access Denied error keeps occurring until I unplug and replug the
> device.  Restarting the program alone doesnt fix it.

libusb under Windows do not support libusb_reset() since WinUSB
driver does not support reset.

BTW, what is the libusb version you are using? You should use the latest
libusb-1.0.19 version.

> I have a multithreaded program, but interaction with pyusb is only ever done
> in the same, single thread.
>
> Anyone have any ideas what's going on?  Or is this something I should ask
> the libusb list about?
>

You can follow Wander's advice to turn on PYUSB_DEBUG=debug for pyusb
debug message. If that is not good enough, you can turn on libusb
debug by setting env variable LIBUSB_DEBUG=4 for libusb debug messages.

And when this happen, you can check if your USB device is still recognized
by Windows in Device Manager? If not, then libusb will fail and most likely
your device has a HW/FW stability problem.


-- 
Xiaofan

[pyusb-users] Help with writing a driver for USB HID device.

[Anatoly V. <an...@gm...>]

Hi,

I'm writing a driver for a device.  It was originally using MDB ICP, but
now it ships with a USB to MDB bridge, why they have chosen to do it as HID
rather then USB Serial i have no idea.  So behind the usb there is a simple
serial protocol.

Here is what lsusb gives:

Bus 001 Device 027: ID 155d:0002
Device Descriptor:
  bLength                18
  bDescriptorType         1
  bcdUSB               1.10
  bDeviceClass            0 (Defined at Interface level)
  bDeviceSubClass         0
  bDeviceProtocol         0
  bMaxPacketSize0         8
  idVendor           0x155d
  idProduct          0x0002
  bcdDevice            2.95
  iManufacturer           1 (error)
  iProduct                2 NRI-USB-HID-DEV-01
  iSerial                 0
  bNumConfigurations      1
  Configuration Descriptor:
    bLength                 9
    bDescriptorType         2
    wTotalLength           34
    bNumInterfaces          1
    bConfigurationValue     1
    iConfiguration          8 Main Configuration
    bmAttributes         0x80
      (Bus Powered)
    MaxPower              100mA
    Interface Descriptor:
      bLength                 9
      bDescriptorType         4
      bInterfaceNumber        0
      bAlternateSetting       0
      bNumEndpoints           1
      bInterfaceClass         3 Human Interface Device
      bInterfaceSubClass      0 No Subclass
      bInterfaceProtocol      0 None
      iInterface              5 Alternate Setting1
        HID Device Descriptor:
          bLength                 9
          bDescriptorType        33
          bcdHID               1.10
          bCountryCode            0 Not supported
          bNumDescriptors         1
          bDescriptorType        34 Report
          wDescriptorLength      30
         Report Descriptors:
           ** UNAVAILABLE **
      Endpoint Descriptor:
        bLength                 7
        bDescriptorType         5
        bEndpointAddress     0x82  EP 2 IN
        bmAttributes            3
          Transfer Type            Interrupt
          Synch Type               None
          Usage Type               Data
        wMaxPacketSize     0x0020  1x 32 bytes
        bInterval               8
Device Status:     0x0001
  Self Powered

I take it, this means one configuration, one interface, one end point.  So
the data should be read from endpoint at address 0x82, and data should be
written to endpoint 0x00 with ctrl_transfer, is that correct?

Here is a SnoopyPro trace of control software running on windows, for
message sent to device:

URB Header (length: 80)
SequenceNumber: 21
Function: 001b (CLASS_INTERFACE)
PipeHandle: 00000000

SetupPacket:
0000: 22 09 00 03 00 00 00 00
bmRequestType: 22
  DIR: Host-To-Device
  TYPE: Class
  RECIPIENT: Endpoint
bRequest: 09

TransferBuffer: 0x00000008 (8) length
0000: 03 02 85 0a 05 14 ff ff


The payload of this is [0x02 0x85 0x0a], that's the init command as
described in device docs. The device replies with this:

URB Header (length: 80)
SequenceNumber: 22
Function: 0008 (CONTROL_TRANSFER)
PipeHandle: 86d039cc

SetupPacket:
0000: a1 01 00 03 00 00 08 00
bmRequestType: a1
  DIR: Device-To-Host
  TYPE: Class
  RECIPIENT: Interface
bRequest: 01

TransferBuffer: 0x00000008 (8) length
0000: 01 2e ff ff ff ff ff ff

Payload of this is [0x2E] again per spec.  Now my goal is to reproduce this
simple exchange, once i have that i can go on to implement all other needed
commands.
I'm guessing that the protocol messages are prepended with message size
byte and padded up to 8 bytes with 0xFF or random data
Curiously snoopyPro generates traces even if the control application is not
loaded, i assume these messages don't make it to the actual device.

Here is the gist of my code:

dev = usb.core.find(idVendor=0x155d, idProduct=0x0002)
# check and remove kernel driver
dev.set_configuration()
dev.reset()
# bmRequestType, bRequest are taken from SnoopyPro trace.
res = dev.ctrl_transfer(0x22, 0x9, 0, 0, [0x02, 0x85, 0x0a], 1000)
data = dev.read(0x82, 32, timeout=10000)

ctrl_transfer fails with USBError(32, 'Pipe error') and
after couple of retries : USBError(19, 'No such device (it may have been
disconnected)')
i have also tried the whole byte string from the capture

res = dev.ctrl_transfer(0x22, 0x9, 0, 0, [0x03, 0x02, 0x85, 0x0a, 0x05,
0x14, 0xff, 0xff], 1000)

to same effect.

So what am i missing?
Why is the trace saying that host to device message is using function 0x1b
(Class interface) and device to host is using function 0x08 (control
transfer), shouldn't it be the other way around?

thanks,
Anatoli

Re: [pyusb-users] Access Denied Error on Windows 7

[Wander L. C. <wan...@gm...>]

2014-11-11 15:22 GMT-02:00 Richard Bryan <ra...@lu...>:
> I'm frequently running into an "Access Denied (insufficient permissions)"
> errors on Windows 7 (with libusb1 backend) during long-running usb sessions
> with a device.  When this happens, I call reset() and dispose_resources() on
> the usb handle and then attempt to reenumerate it using usb.core.find(), but
> the Access Denied error keeps occurring until I unplug and replug the
> device.  Restarting the program alone doesnt fix it.
>

iirc, libusb reset operation is problematic under Windows, so better
to avoid it.

> I have a multithreaded program, but interaction with pyusb is only ever done
> in the same, single thread.
>

This should not cause problems...

> Anyone have any ideas what's going on?  Or is this something I should ask
> the libusb list about?
>

Could you please run you program with the environment variable
PYUSB_DEBUG=debug defined and report the logs?

> Richard
>
> ------------------------------------------------------------------------------
> Comprehensive Server Monitoring with Site24x7.
> Monitor 10 servers for $9/Month.
> Get alerted through email, SMS, voice calls or mobile push notifications.
> Take corrective actions from your mobile device.
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> _______________________________________________
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> pyu...@li...
> https://lists.sourceforge.net/lists/listinfo/pyusb-users
>



-- 
Best Regards,
Wander Lairson Costa

[pyusb-users] Access Denied Error on Windows 7

[Richard B. <ra...@lu...>]

I'm frequently running into an "Access Denied (insufficient permissions)"
errors on Windows 7 (with libusb1 backend) during long-running usb sessions
with a device.  When this happens, I call reset() and dispose_resources()
on the usb handle and then attempt to reenumerate it using usb.core.find(),
but the Access Denied error keeps occurring until I unplug and replug the
device.  Restarting the program alone doesnt fix it.

I have a multithreaded program, but interaction with pyusb is only ever
done in the same, single thread.

Anyone have any ideas what's going on?  Or is this something I should ask
the libusb list about?

Richard

[pyusb-users] now we're cooking

[Anony M. <fy...@gm...>]

> $ python
>>> import ctypes
>>> import ctypes.util
>>> ctypes.util.find_library('libusb-1.0')

> Does it work on your environment?

No. But it does give a hint!

=====================

Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
  File
"/System/Library/Frameworks/Python.framework/Versions/2.6/lib/python2.6/ctypes/__init__.py",
line 423, in LoadLibrary
    return self._dlltype(name)
  File
"/System/Library/Frameworks/Python.framework/Versions/2.6/lib/python2.6/ctypes/__init__.py",
line 345, in __init__
    self._handle = _dlopen(self._name, mode)
OSError: dlopen(libusb-1.0.dylib, 6): no suitable image found.  *Did find:*
* /usr/local/lib/libusb-1.0.dylib: mach-o, but wrong architecture*
>>>

==========================

Thus:

==> file libusb-1.0.0.dylib

libusb-1.0.0.dylib: Mach-O 64-bit dynamically linked shared library x86_64

so.... I need 32 bit. ok then:

==> sudo rm -f /usr/local/lib/libusb*
==> sudo make clean
==> sudo ./configure CXXFLAGS="-m32 -arch 386" CFLAGS="-m32"
==> sudo make
==> sudo make install

Python ctypes check now returns:

>>> import ctypes
>>> import ctypes.util as x
>>> x.find_library('libusb-1.0')
'/usr/local/lib/libusb-1.0.dylib'
>>>

...which looks good, so I messed with some more testcode, and as long as I
do this first...

mybackend = usb.backend.libusb1.get_backend(find_library=lambda x:
"/usr/local/lib/libusb-1.0.dylib')

...then usb.lib and usb.core act reasonably.

Still not sure why it's not finding the library itself, though.

Thanks for the help, everyone. Kudos to the bunch of yas. :)

Re: [pyusb-users] Continuous monitoring of 3 USB scales

[Jared C. <jar...@li...>]

Mark--

To add to Ian's response, the HID POS Usage Tables (
http://www.usb.org/developers/hidpage/pos1_02.pdf) will help you decipher
what the HID kernel module is telling you. Check out "Section 4 Weighing
Devices (0x8D)" for the Report IDs, which will put context to the data that
you receive from the HID driver.

I'm working on a similar project using a Dymo Pelouze 25 lb. Postal Scale.

Best of luck!

--Jared

On Mon, Nov 3, 2014 at 2:44 PM, Ian Daniher <it....@gm...> wrote:

> If you haven't already, I'd start by generating large log files of the
> scales interacting with the vendor-provided software. It's easy to do this
> on Linux using https://www.kernel.org/doc/Documentation/usb/usbmon.txt.
>
> Also, you have a USB HID device, which is a shortpath used by many vendors
> for "driverless" operation. Unfortunately this will make direct PyUSB
> interface slightly obnoxious. I'd check out
> http://pythonic-wisdom.blogspot.com/2009/07/usb-hid-with-linux-and-python.html
> and continue the search from there, looking less at PyUSB and perhaps more
> at the source of existing Python+USB+HID projects.
>
> BR,
> Ian
>
>
>
> On Mon, Nov 3, 2014 at 2:34 PM, Mark McClure <mar...@gm...>
> wrote:
>
>> Wander and all users,
>>
>> Thank you for getting back to me. As you can tell, all of this is foreign
>> to me since I'm a very novice programmer.  When you say poll the USB POV,
>> do you mean "read" data from the device?
>>
>> Here's what I tried as I removed jelly beans from a scale over 10 seconds:
>>
>> import sys
>> import usb.core
>> import usb.util
>> import time
>>
>> dev = usb.core.find(idVendor = 0x0DBC, idProduct = 0x0005)
>> if dev is None:
>>     raise ValueError('Device not found')
>>
>> dev.set_configuration()
>>
>> endpoint = dev[0][(0,0)][0]
>>
>> timestep = 0
>>
>> while timestep <= 10:
>>     data = dev.read(endpoint.bEndpointAddress,
>>            endpoint.wMaxPacketSize)
>>     print(data)
>>     time.sleep(1)
>>     timestep += 1
>>
>>
>> The output was this:
>>
>> array('B', [0, 0, 87, 0, 0, 0, 0, 0])
>> array('B', [0, 0, 0, 0, 0, 0, 0, 0])
>> array('B', [0, 0, 98, 0, 0, 0, 0, 0])
>> array('B', [0, 0, 0, 0, 0, 0, 0, 0])
>> array('B', [0, 0, 98, 0, 0, 0, 0, 0])
>> array('B', [0, 0, 0, 0, 0, 0, 0, 0])
>> array('B', [0, 0, 98, 0, 0, 0, 0, 0])
>> array('B', [0, 0, 0, 0, 0, 0, 0, 0])
>> array('B', [0, 0, 98, 0, 0, 0, 0, 0])
>> array('B', [0, 0, 0, 0, 0, 0, 0, 0])
>> array('B', [0, 0, 96, 0, 0, 0, 0, 0])
>>
>> But I don't have any idea what this means, except that I'm guessing that
>> changes in weight data were not recorded.
>>
>> Has anyone worked on a device like this?  Some sample code might really
>> help me make sense of everything.
>>
>> On Mon, Nov 3, 2014 at 2:31 AM, Wander Lairson Costa <
>> wan...@gm...> wrote:
>>
>>> 2014-11-02 1:54 GMT-02:00 Mark McClure <mar...@gm...>:
>>> > Hello list:
>>> >
>>> > I have three A&D EJ-3000 scales that I want to simultaneously acquire
>>> data
>>> > from every 1 minute over 24-hr periods.  All scales have a USB
>>> interface.
>>> > I've started working through the pyusb tutorial, but before I confuse
>>> myself
>>> > any further, I thought I'd ask if what I want to do is even possible?
>>> Tech
>>> > support at A&D told me that retrieving weight data from the scales
>>> > automatically (i.e. without pushing the print button on the scales)
>>> could
>>> > not be done with USB because the interface was uni-directional.
>>> Instead,
>>> > they suggested that I switch to RS-232.  Is this true, and if so why?
>>> >
>>>
>>> Hi,
>>>
>>> It really depends on how the firmware behaves, from USB POV, you can
>>> always poll the device for data each minute. But might be other
>>> constraints that I am not aware of.
>>>
>>> > I printed the configuration of the scale after installing pyusb and
>>> starting
>>> > the tutorial.
>>> >
>>> >
>>> > CONFIGURATION 1: 20 mA ===================================
>>> >    bLength              :    0x9 (9 bytes)
>>> >    bDescriptorType      :    0x2 Configuration
>>> >    wTotalLength         :   0x2d (45 bytes)
>>> >    bNumInterfaces       :    0x1
>>> >    bConfigurationValue  :    0x1
>>> >    iConfiguration       :    0x0
>>> >    bmAttributes         :   0x80 Bus Powered
>>> >    bMaxPower            :    0xa (20 mA)
>>> >     INTERFACE 0: Human Interface Device ====================
>>> >      bLength            :    0x9 (9 bytes)
>>> >      bDescriptorType    :    0x4 Interface
>>> >      bInterfaceNumber   :    0x0
>>> >      bAlternateSetting  :    0x0
>>> >      bNumEndpoints      :    0x2
>>> >      bInterfaceClass    :    0x3 Human Interface Device
>>> >      bInterfaceSubClass :    0x0
>>> >      bInterfaceProtocol :    0x1
>>> >      iInterface         :    0x0
>>> >       ENDPOINT 0x81: Interrupt IN ==========================
>>> >        bLength          :    0x7 (7 bytes)
>>> >        bDescriptorType  :    0x5 Endpoint
>>> >        bEndpointAddress :   0x81 IN
>>> >        bmAttributes     :    0x3 Interrupt
>>> >        wMaxPacketSize   :   0x40 (64 bytes)
>>> >        bInterval        :    0x4
>>> >       ENDPOINT 0x2: Interrupt OUT ==========================
>>> >        bLength          :    0x7 (7 bytes)
>>> >        bDescriptorType  :    0x5 Endpoint
>>> >        bEndpointAddress :    0x2 OUT
>>> >        bmAttributes     :    0x3 Interrupt
>>> >        wMaxPacketSize   :   0x40 (64 bytes)
>>> >        bInterval        :    0x4
>>> >
>>> > Any guidance would be greatly appreciated.
>>> >
>>>
>>>
>>> --
>>> Best Regards,
>>> Wander Lairson Costa
>>>
>>>
>>> ------------------------------------------------------------------------------
>>> _______________________________________________
>>> pyusb-users mailing list
>>> pyu...@li...
>>> https://lists.sourceforge.net/lists/listinfo/pyusb-users
>>>
>>
>>
>>
>> ------------------------------------------------------------------------------
>>
>> _______________________________________________
>> pyusb-users mailing list
>> pyu...@li...
>> https://lists.sourceforge.net/lists/listinfo/pyusb-users
>>
>>
>
>
> ------------------------------------------------------------------------------
>
> _______________________________________________
> pyusb-users mailing list
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>

Re: [pyusb-users] Continuous monitoring of 3 USB scales

[Ian D. <it....@gm...>]

If you haven't already, I'd start by generating large log files of the
scales interacting with the vendor-provided software. It's easy to do this
on Linux using https://www.kernel.org/doc/Documentation/usb/usbmon.txt.

Also, you have a USB HID device, which is a shortpath used by many vendors
for "driverless" operation. Unfortunately this will make direct PyUSB
interface slightly obnoxious. I'd check out
http://pythonic-wisdom.blogspot.com/2009/07/usb-hid-with-linux-and-python.html
and continue the search from there, looking less at PyUSB and perhaps more
at the source of existing Python+USB+HID projects.

BR,
Ian



On Mon, Nov 3, 2014 at 2:34 PM, Mark McClure <mar...@gm...> wrote:

> Wander and all users,
>
> Thank you for getting back to me. As you can tell, all of this is foreign
> to me since I'm a very novice programmer.  When you say poll the USB POV,
> do you mean "read" data from the device?
>
> Here's what I tried as I removed jelly beans from a scale over 10 seconds:
>
> import sys
> import usb.core
> import usb.util
> import time
>
> dev = usb.core.find(idVendor = 0x0DBC, idProduct = 0x0005)
> if dev is None:
>     raise ValueError('Device not found')
>
> dev.set_configuration()
>
> endpoint = dev[0][(0,0)][0]
>
> timestep = 0
>
> while timestep <= 10:
>     data = dev.read(endpoint.bEndpointAddress,
>            endpoint.wMaxPacketSize)
>     print(data)
>     time.sleep(1)
>     timestep += 1
>
>
> The output was this:
>
> array('B', [0, 0, 87, 0, 0, 0, 0, 0])
> array('B', [0, 0, 0, 0, 0, 0, 0, 0])
> array('B', [0, 0, 98, 0, 0, 0, 0, 0])
> array('B', [0, 0, 0, 0, 0, 0, 0, 0])
> array('B', [0, 0, 98, 0, 0, 0, 0, 0])
> array('B', [0, 0, 0, 0, 0, 0, 0, 0])
> array('B', [0, 0, 98, 0, 0, 0, 0, 0])
> array('B', [0, 0, 0, 0, 0, 0, 0, 0])
> array('B', [0, 0, 98, 0, 0, 0, 0, 0])
> array('B', [0, 0, 0, 0, 0, 0, 0, 0])
> array('B', [0, 0, 96, 0, 0, 0, 0, 0])
>
> But I don't have any idea what this means, except that I'm guessing that
> changes in weight data were not recorded.
>
> Has anyone worked on a device like this?  Some sample code might really
> help me make sense of everything.
>
> On Mon, Nov 3, 2014 at 2:31 AM, Wander Lairson Costa <
> wan...@gm...> wrote:
>
>> 2014-11-02 1:54 GMT-02:00 Mark McClure <mar...@gm...>:
>> > Hello list:
>> >
>> > I have three A&D EJ-3000 scales that I want to simultaneously acquire
>> data
>> > from every 1 minute over 24-hr periods.  All scales have a USB
>> interface.
>> > I've started working through the pyusb tutorial, but before I confuse
>> myself
>> > any further, I thought I'd ask if what I want to do is even possible?
>> Tech
>> > support at A&D told me that retrieving weight data from the scales
>> > automatically (i.e. without pushing the print button on the scales)
>> could
>> > not be done with USB because the interface was uni-directional.
>> Instead,
>> > they suggested that I switch to RS-232.  Is this true, and if so why?
>> >
>>
>> Hi,
>>
>> It really depends on how the firmware behaves, from USB POV, you can
>> always poll the device for data each minute. But might be other
>> constraints that I am not aware of.
>>
>> > I printed the configuration of the scale after installing pyusb and
>> starting
>> > the tutorial.
>> >
>> >
>> > CONFIGURATION 1: 20 mA ===================================
>> >    bLength              :    0x9 (9 bytes)
>> >    bDescriptorType      :    0x2 Configuration
>> >    wTotalLength         :   0x2d (45 bytes)
>> >    bNumInterfaces       :    0x1
>> >    bConfigurationValue  :    0x1
>> >    iConfiguration       :    0x0
>> >    bmAttributes         :   0x80 Bus Powered
>> >    bMaxPower            :    0xa (20 mA)
>> >     INTERFACE 0: Human Interface Device ====================
>> >      bLength            :    0x9 (9 bytes)
>> >      bDescriptorType    :    0x4 Interface
>> >      bInterfaceNumber   :    0x0
>> >      bAlternateSetting  :    0x0
>> >      bNumEndpoints      :    0x2
>> >      bInterfaceClass    :    0x3 Human Interface Device
>> >      bInterfaceSubClass :    0x0
>> >      bInterfaceProtocol :    0x1
>> >      iInterface         :    0x0
>> >       ENDPOINT 0x81: Interrupt IN ==========================
>> >        bLength          :    0x7 (7 bytes)
>> >        bDescriptorType  :    0x5 Endpoint
>> >        bEndpointAddress :   0x81 IN
>> >        bmAttributes     :    0x3 Interrupt
>> >        wMaxPacketSize   :   0x40 (64 bytes)
>> >        bInterval        :    0x4
>> >       ENDPOINT 0x2: Interrupt OUT ==========================
>> >        bLength          :    0x7 (7 bytes)
>> >        bDescriptorType  :    0x5 Endpoint
>> >        bEndpointAddress :    0x2 OUT
>> >        bmAttributes     :    0x3 Interrupt
>> >        wMaxPacketSize   :   0x40 (64 bytes)
>> >        bInterval        :    0x4
>> >
>> > Any guidance would be greatly appreciated.
>> >
>>
>>
>> --
>> Best Regards,
>> Wander Lairson Costa
>>
>>
>> ------------------------------------------------------------------------------
>> _______________________________________________
>> pyusb-users mailing list
>> pyu...@li...
>> https://lists.sourceforge.net/lists/listinfo/pyusb-users
>>
>
>
>
> ------------------------------------------------------------------------------
>
> _______________________________________________
> pyusb-users mailing list
> pyu...@li...
> https://lists.sourceforge.net/lists/listinfo/pyusb-users
>
>

Re: [pyusb-users] Continuous monitoring of 3 USB scales

[Mark M. <mar...@gm...>]

Wander and all users,

Thank you for getting back to me. As you can tell, all of this is foreign
to me since I'm a very novice programmer.  When you say poll the USB POV,
do you mean "read" data from the device?

Here's what I tried as I removed jelly beans from a scale over 10 seconds:

import sys
import usb.core
import usb.util
import time

dev = usb.core.find(idVendor = 0x0DBC, idProduct = 0x0005)
if dev is None:
    raise ValueError('Device not found')

dev.set_configuration()

endpoint = dev[0][(0,0)][0]

timestep = 0

while timestep <= 10:
    data = dev.read(endpoint.bEndpointAddress,
           endpoint.wMaxPacketSize)
    print(data)
    time.sleep(1)
    timestep += 1


The output was this:

array('B', [0, 0, 87, 0, 0, 0, 0, 0])
array('B', [0, 0, 0, 0, 0, 0, 0, 0])
array('B', [0, 0, 98, 0, 0, 0, 0, 0])
array('B', [0, 0, 0, 0, 0, 0, 0, 0])
array('B', [0, 0, 98, 0, 0, 0, 0, 0])
array('B', [0, 0, 0, 0, 0, 0, 0, 0])
array('B', [0, 0, 98, 0, 0, 0, 0, 0])
array('B', [0, 0, 0, 0, 0, 0, 0, 0])
array('B', [0, 0, 98, 0, 0, 0, 0, 0])
array('B', [0, 0, 0, 0, 0, 0, 0, 0])
array('B', [0, 0, 96, 0, 0, 0, 0, 0])

But I don't have any idea what this means, except that I'm guessing that
changes in weight data were not recorded.

Has anyone worked on a device like this?  Some sample code might really
help me make sense of everything.

On Mon, Nov 3, 2014 at 2:31 AM, Wander Lairson Costa <
wan...@gm...> wrote:

> 2014-11-02 1:54 GMT-02:00 Mark McClure <mar...@gm...>:
> > Hello list:
> >
> > I have three A&D EJ-3000 scales that I want to simultaneously acquire
> data
> > from every 1 minute over 24-hr periods.  All scales have a USB interface.
> > I've started working through the pyusb tutorial, but before I confuse
> myself
> > any further, I thought I'd ask if what I want to do is even possible?
> Tech
> > support at A&D told me that retrieving weight data from the scales
> > automatically (i.e. without pushing the print button on the scales) could
> > not be done with USB because the interface was uni-directional.  Instead,
> > they suggested that I switch to RS-232.  Is this true, and if so why?
> >
>
> Hi,
>
> It really depends on how the firmware behaves, from USB POV, you can
> always poll the device for data each minute. But might be other
> constraints that I am not aware of.
>
> > I printed the configuration of the scale after installing pyusb and
> starting
> > the tutorial.
> >
> >
> > CONFIGURATION 1: 20 mA ===================================
> >    bLength              :    0x9 (9 bytes)
> >    bDescriptorType      :    0x2 Configuration
> >    wTotalLength         :   0x2d (45 bytes)
> >    bNumInterfaces       :    0x1
> >    bConfigurationValue  :    0x1
> >    iConfiguration       :    0x0
> >    bmAttributes         :   0x80 Bus Powered
> >    bMaxPower            :    0xa (20 mA)
> >     INTERFACE 0: Human Interface Device ====================
> >      bLength            :    0x9 (9 bytes)
> >      bDescriptorType    :    0x4 Interface
> >      bInterfaceNumber   :    0x0
> >      bAlternateSetting  :    0x0
> >      bNumEndpoints      :    0x2
> >      bInterfaceClass    :    0x3 Human Interface Device
> >      bInterfaceSubClass :    0x0
> >      bInterfaceProtocol :    0x1
> >      iInterface         :    0x0
> >       ENDPOINT 0x81: Interrupt IN ==========================
> >        bLength          :    0x7 (7 bytes)
> >        bDescriptorType  :    0x5 Endpoint
> >        bEndpointAddress :   0x81 IN
> >        bmAttributes     :    0x3 Interrupt
> >        wMaxPacketSize   :   0x40 (64 bytes)
> >        bInterval        :    0x4
> >       ENDPOINT 0x2: Interrupt OUT ==========================
> >        bLength          :    0x7 (7 bytes)
> >        bDescriptorType  :    0x5 Endpoint
> >        bEndpointAddress :    0x2 OUT
> >        bmAttributes     :    0x3 Interrupt
> >        wMaxPacketSize   :   0x40 (64 bytes)
> >        bInterval        :    0x4
> >
> > Any guidance would be greatly appreciated.
> >
>
>
> --
> Best Regards,
> Wander Lairson Costa
>
>
> ------------------------------------------------------------------------------
> _______________________________________________
> pyusb-users mailing list
> pyu...@li...
> https://lists.sourceforge.net/lists/listinfo/pyusb-users
>

Re: [pyusb-users] Further info

[Emmanuel B. <ebl...@gm...>]

> It hasn't. This is a fresh compile under 10.6.8. I am trying -- hard -- to
> avoid using homebrew and similar.

I personally never broke my systems with Homebrew (but I did several
time with MacPorts and Fink), and I now use it intensively, but I
guess that YMMV.

> Adding libusb path to DYLD_LIBRARY_PATH should be enough.
> export DYLD_FALLBACK_LIBRARY_PATH=/usr/local/lib
> export DYLD_LIBRARY_PATH=/usr/local/lib

It should, but in any case you do not need both (remove
DYLD_FALLBACK_LIBRARY_PATH, although it does not hurt)

> It doesn't appear that the DEBUG log command does anything, but this is
> still just trying to get libusb to wake up, so I wouldn't expect it to.

Maybe you should try to move one step downwards and check what
Python'c ctypes is able to load:

$ python
>>> import ctypes
>>> import ctypes.util
>>> ctypes.util.find_library('libusb-1.0')

should return

  /usr/local/lib/libusb-1.0.dylib

>>> ctypes.cdll.LoadLibrary('libusb-1.0.dylib')

should return

  <CDLL 'libusb-1.0.dylib', handle ...>

Does it work on your environment?

Cheers,
Manu