If compiled using MinGW, the compiler will dump an error stating that storage
size of some variable isn't known. Those variables are declared as
struct timespec type. The reason is because the data structure is not
defined under time.h header. It is included in unistd.h header. So by
including the additional header into the offending C files, the problem
will be solved.
Note: If compiled under MinGW, do not use Git Bash. Use MYS Bash, instead.
This is to avoid failure during configure or make.
First install PyUSB through pip if you haven't done so:
pip install pyusb
PyUSB relies on a USB library backend to function. In our case, we will use
libusb-1.0.dll obviously. After running:
./configure --prefix=/C/Tools
make
make install
The DLL can be found in /C/Tools/bin folder. Copy it to /C/Windows/System32
and another copy to /C/Windows/SysWOW64. Note that PyUSB uses
ctypes.util.find_library() function to locate the library. If a copy of the
DLL is not copied into /C/Windows/SysWOW64, the function will fail to locate
it. I don't know why. Once that is done, open up Python IDLE and type:
from ctypes.util import find_library
find_library(r"libusb-1.0.dll")
It should return C:\\Windows\\system32\\libusb-1.0.dll and you are good to
go. If nothing is displayed, it means it cannot find the library. Re-examine
the steps given above to make sure you have not done any mistake.
To use the PyUSB type:
import usb.core
dev = usb.core.find()
which should return no result. If there is any exception raised, probably the backend USB library is not there. Please read the previous section.
The following example is for ST-Link dongle:
import usb.core
dev = usb.core.find(idVendor=0x0483, idProduct=0x3748)
dev.set_configuration()
cfg = dev.get_active_configuration() # Get configuration descriptor
intf = cfg[(0,0)] # Get the 1st interface descriptor
ep = usb.util.find_descriptor( # Get the 1st OUT endpoint descriptor
intf,
# match the first OUT endpoint
custom_match = \
lambda e: \
usb.util.endpoint_direction(e.bEndpointAddress) == \
usb.util.ENDPOINT_OUT)
print(ep) # Print the OUT end-point
print(intf) # Print the interface
print(cfg) # Print the configuration
usb.core.util.get_string(dev, 1) # Returns 'STMicroelectronics'
usb.core.util.get_string(dev, 2) # Returns 'STM32 STLink'
usb.core.util.get_string(dev, 4) # Returns 'ST Link'
We can show all USB devices:
usb.core.show_devices()
When there are multiple ST-Link dongles, pyusb is able to list each one of them.
They are differentiated by bus and address:
usb.core.show_devices(idVendor=0x483, idProduct=0x3748)
If the details of the devices are also needed, type:
usb.core.show_devices(verbose=True, idVendor=0x483, idProduct=0x3748)
The following code snippet shows another way to find all devices on the USB bus
with the same idVendor and idProduct (identical devices):
devices = usb.core.find(find_all = True, idVendor=0x483, idProduct=0x3748)
for device in devices:
print("device=%x:%x, bus=%d, address=%d" % \
(device.idVendor, device.idProduct, device.bus, device.address))
The following shows how to retrieve the serial number of the ST-Link dongles:
devs = usb.core.find(find_all=True, idVendor=0x0483, idProduct=0x3748)
for dev in devs:
print("device=%x:%x on " % (dev.idVendor, dev.idProduct), end='')
print("bus:addr=%x:%x, serial-num=" % (dev.bus, dev.address), end='')
for b in dev.serial_number.encode():
print("%x" % b, end='')
print()
However, the serial number retrieved seems to be incorrect at certain locations. For further examples, refer to [1].
This source code was retrieved from [2].