Send commands to USB device in Python
andre.miras at gmail.com
andre.miras at gmail.com
Mon May 26 14:25:51 EDT 2014
Hi,
I saw your thread on SourceFourge (http://sourceforge.net/p/pyusb/mailman/message/31969943/), but I don't have an account.
I also have MTI RU-824 reader. I sniffed the USB communication in the Windows demo program and I saw that the header should be written backward.
So rather than:
HEADER = bytearray("MTIC")
try:
HEADER = bytearray("MTIC"[::-1])
I tested it and it works.
On Tuesday, 11 February 2014 06:55:03 UTC+1, Setia Budi wrote:
> Hi fellows,
>
> I am facing difficulties in order to send USB commands to an RFID reader.
>
> This is the command reference of the device: https://github.com/mti-rfid/RFID_Explorer
>
>
>
> I am working with the MTI RU-824 model.
>
>
>
> The manufacturer of the device only provide a driver for Windows (using .Net), but we need to run the device on Linux. That's why I need to write few lines of code in Python as a new "driver".
>
>
>
> I am using PyUSB for accessing the device, and this is few lines of my code:
>
>
>
> ============================================================================
>
>
>
> import usb.core
>
> import usb.util
>
> import sys
>
>
>
> VENDOR_ID = 0x24e9
>
> PRODUCT_ID = 0x0824
>
>
>
> device = usb.core.find(idVendor=VENDOR_ID, idProduct=PRODUCT_ID)
>
>
>
> if device is None:
>
> sys.exit("Could not find Id System Barcode Reader.")
>
> else:
>
> print 'Device detected'
>
>
>
> device.set_configuration()
>
>
>
> cfg = device.get_active_configuration()
>
> interface_number = cfg[(0, 0)].bInterfaceNumber
>
> alternate_setting = usb.control.get_interface(device, interface_number)
>
> usb_interface = usb.util.find_descriptor(
>
> cfg, bInterfaceNumber=interface_number,
>
> bAlternateSetting=alternate_setting
>
> )
>
>
>
> endpoint_out = usb.util.find_descriptor(
>
> usb_interface,
>
> # match the first OUT endpoint
>
> custom_match=lambda e: usb.util.endpoint_direction(e.bEndpointAddress) == usb.util.ENDPOINT_OUT
>
> )
>
>
>
> endpoint_in = usb.util.find_descriptor(
>
> usb_interface,
>
> # match the first IN endpoint
>
> custom_match=lambda e: usb.util.endpoint_direction(e.bEndpointAddress) == usb.util.ENDPOINT_IN
>
> )
>
>
>
> endpoint_out.write('0x01')
>
> print endpoint_in.read(len('0x01'), 1000)
>
>
>
> =============================================================================
>
> My question is on the last 2 lines.
>
> I am using endpoint_out to send a command and endpoint_in to read data from the reader. Am I correct?
>
>
>
> The problem is, when I run the code, there is an error message like this:
>
> usb.core.USBError: [Errno 110] Operation timed out
>
>
>
> Anyone can give a clue?
>
> Thank you.
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