Unfortunately, again I am experiencing some problems with communication via USB with PyUSB under Windows. In my question about 2-3 years ago, the problem was that the vendor provided wrong documentation and wrong SCPI commands.
Now, I would like to communicate with a stepper-motor controller (TMCM-6110) from Trinamic. Everything works fine with the IDE from the vendor, but now I want to address the device via pyusb, starting again from this pyusb-tutorial.
The device is found, so I assume:
- libusb is installed correctly and found
- idVendor and idProduct are correct
The commands I have to send are fixed 9 bytes messages.
For example: "move to position absolute motor0 12800 steps".
The byte sequence is: b'\x01\x04\x01\x00\x00\x00\x32\x01\x39' which, however, Python prints as b'\x01\x04\x01\x00\x00\x002\x019' which confused me and took me a while to figure out that this is the same.
From the output from print(dev), I assume that the address is 3.
However, I get error messages:
Script:
import usb.core
import usb.util
dev = usb.core.find(idVendor=0x2a3c, idProduct=0x0100)
if dev is None:
raise ValueError('Device is not found')
# device is found :-)
print(dev)
cmd = b'\x01\x04\x01\x00\x00\x002\x019'
# cmd = b'\x01\x04\x01\x00\x00\x00\x32\x01\x39'
dev.write(3,cmd)
Output:
DEVICE ID 2a3c:0100 on Bus 001 Address 006 =================
bLength : 0x12 (18 bytes)
bDescriptorType : 0x1 Device
bcdUSB : 0x110 USB 1.1
bDeviceClass : 0x2 Communications Device
bDeviceSubClass : 0x0
bDeviceProtocol : 0x0
bMaxPacketSize0 : 0x40 (64 bytes)
idVendor : 0x2a3c
idProduct : 0x0100
bcdDevice : 0x2e01 Device 46.01
iManufacturer : 0x1 Error Accessing String
iProduct : 0x2 Error Accessing String
iSerialNumber : 0x3 Error Accessing String
bNumConfigurations : 0x1
CONFIGURATION 1: 100 mA ==================================
bLength : 0x9 (9 bytes)
bDescriptorType : 0x2 Configuration
wTotalLength : 0x43 (67 bytes)
bNumInterfaces : 0x2
bConfigurationValue : 0x1
iConfiguration : 0x0
bmAttributes : 0xc0 Self Powered
bMaxPower : 0x32 (100 mA)
INTERFACE 0: CDC Communication =========================
bLength : 0x9 (9 bytes)
bDescriptorType : 0x4 Interface
bInterfaceNumber : 0x0
bAlternateSetting : 0x0
bNumEndpoints : 0x1
bInterfaceClass : 0x2 CDC Communication
bInterfaceSubClass : 0x2
bInterfaceProtocol : 0x1
iInterface : 0x0
ENDPOINT 0x82: Interrupt IN ==========================
bLength : 0x7 (7 bytes)
bDescriptorType : 0x5 Endpoint
bEndpointAddress : 0x82 IN
bmAttributes : 0x3 Interrupt
wMaxPacketSize : 0x8 (8 bytes)
bInterval : 0xff
INTERFACE 1: CDC Data ==================================
bLength : 0x9 (9 bytes)
bDescriptorType : 0x4 Interface
bInterfaceNumber : 0x1
bAlternateSetting : 0x0
bNumEndpoints : 0x2
bInterfaceClass : 0xa CDC Data
bInterfaceSubClass : 0x0
bInterfaceProtocol : 0x0
iInterface : 0x0
ENDPOINT 0x3: Bulk OUT ===============================
bLength : 0x7 (7 bytes)
bDescriptorType : 0x5 Endpoint
bEndpointAddress : 0x3 OUT
bmAttributes : 0x2 Bulk
wMaxPacketSize : 0x40 (64 bytes)
bInterval : 0x0
ENDPOINT 0x81: Bulk IN ===============================
bLength : 0x7 (7 bytes)
bDescriptorType : 0x5 Endpoint
bEndpointAddress : 0x81 IN
bmAttributes : 0x2 Bulk
wMaxPacketSize : 0x40 (64 bytes)
bInterval : 0x0
Error 1:
Traceback (most recent call last):
File "C:\Tilman\Programs\Python37\lib\site-packages\usb\core.py", line 223, in get_interface_and_endpoint
return self._ep_info[endpoint_address]
KeyError: 3
Error 2:
During handling of the above exception, another exception occurred:
Traceback (most recent call last):
File "Trinamic.py", line 13, in <module>
dev.write(3,cmd)
File "C:\Test\Programs\Python37\lib\site-packages\usb\core.py", line 940, in write
intf, ep = self._ctx.setup_request(self, endpoint)
File "C:\Test\Programs\Python37\lib\site-packages\usb\core.py", line 102, in wrapper
return f(self, *args, **kwargs)
File "C:\Test\Programs\Python37\lib\site-packages\usb\core.py", line 215, in setup_request
intf, ep = self.get_interface_and_endpoint(device, endpoint_address)
File "C:\Test\Programs\Python37\lib\site-packages\usb\core.py", line 102, in wrapper
return f(self, *args, **kwargs)
File "C:\Test\Programs\Python37\lib\site-packages\usb\core.py", line 225, in get_interface_and_endpoint
for intf in self.get_active_configuration(device):
File "C:\Test\Programs\Python37\lib\site-packages\usb\core.py", line 102, in wrapper
return f(self, *args, **kwargs)
File "C:\Test\Programs\Python37\lib\site-packages\usb\core.py", line 236, in get_active_configuration
self.managed_open()
File "C:\Test\Programs\Python37\lib\site-packages\usb\core.py", line 102, in wrapper
return f(self, *args, **kwargs)
File "C:\Test\Programs\Python37\lib\site-packages\usb\core.py", line 120, in managed_open
self.handle = self.backend.open_device(self.dev)
File "C:\Test\Programs\Python37\lib\site-packages\usb\backend\libusb1.py", line 786, in open_device
return _DeviceHandle(dev)
File "C:\Test\Programs\Python37\lib\site-packages\usb\backend\libusb1.py", line 643, in __init__
_check(_lib.libusb_open(self.devid, byref(self.handle)))
File "C:\Test\Programs\Python37\lib\site-packages\usb\backend\libusb1.py", line 593, in _check
raise NotImplementedError(_strerror(ret))
NotImplementedError: Operation not supported or unimplemented on this platform
Questions:
Error 1: What does
KeyError: 3mean? Is 3 the wrong address?Error 2: What does
"NotImplementedError: Operation not supported or unimplemented on this platform"mean? How to fix?What else to check and try in order to find out what's going wrong here?
And why can't these communication examples, no matter which interface (RS232, RS458, USB, LAN, ... ) be complete and working right away?
