Does PyUSB raise any exception? If so, what's the message? If not, has
all the data written?
Wander
2008/3/19, Mike Holloway <[EMAIL PROTECTED]>:
> Hi all,
>
> I'm very new to this list, so hello all!
> I'm just starting out using python, my background is lamp.
>
> I have a Prolific Technologies bridged usb cable that I wish to talk to
> using pyusb and libusb, I've tried following examples and compiling my
> own code but I'm really struggling getting it to work.
>
> I'm trying to send a sequence of letters to the cable, for them to
> reappear on the other side. I've been trying to use bulkWrite and
> bulkRead methods but I'm not sure I'm using them right. There's also
> controlMethod, but I'm not sure what that is used for.
>
> Can anyone help get me started, I'm concerned mostly with the
> communication, I reckon I could actually get somewhere if I can just
> nail the first bit, here's my code so far:
>
> * Cheers in advance, Mike.
>
>
> import usb
> import sys
> import os
> import time
> from array import array
>
> class DeviceDescriptor:
> def __init__(self, vendor_id, product_id, interface_id) :
> self.vendor_id = vendor_id
> self.product_id = product_id
> self.interface_id = interface_id
>
> def get_device(self) :
> buses = usb.busses()
> for bus in buses :
> for device in bus.devices :
> if device.idVendor == self.vendor_id :
> if device.idProduct == self.product_id :
> return device
> return None
>
> class XFPS():
> VENDOR_ID = 0x067B #: Vendor Id
> PRODUCT_ID = 0x0000 #: Product Id for the bridged usb cable
> INTERFACE_ID = 0 #: The interface we use to talk to the device
> BULK_IN_EP = 0x83 #: Endpoint for Bulk reads
> BULK_OUT_EP = 0x02 #: Endpoint for Bulk writes
> PACKET_LENGTH = 0x40 #: 64 bytes
>
> device_descriptor = DeviceDescriptor(VENDOR_ID, \
> PRODUCT_ID, INTERFACE_ID)
>
> def __init__(self,) :
> # The actual device (PyUSB object)
> self.device = self.device_descriptor.get_device()
> # Handle that is used to communicate with device. Setup in L{open}
> self.handle = None
>
> def open(self) :
> self.device = self.device_descriptor.get_device()
> if not self.device:
> print >> sys.stderr, "Cable isn't plugged in"
> try:
> self.handle = self.device.open()
> self.handle.claimInterface(self.device_descriptor.interface_id)
> except usb.USBError, err:
> print >> sys.stderr, err
>
> def close(self):
> """ Release device interface """
> try:
> self.handle.reset()
> self.handle.releaseInterface()
> except Exception, err:
> print >> sys.stderr, err
> self.handle, self.device = None, None
>
> def my_bulk_write(self):
> A = chr(0x75) # u
> B = chr(0x69) # i
> X = chr(0x6F) # o
> Y = chr(0x70) # p
> LB = chr(0x6C) # l
> RB = chr(0x6B) # k
> LT = chr(0x68) # h
> RT = chr(0x6A) # j
>
> S = chr(0x32)
> s = chr(0x73)
>
> self.close()
> self.open()
>
> msg = [A,B,A,B,A,B,A,B]
> #help(self.handle.bulkWrite)
> help(self.handle.interruptWrite)
> sent_bytes = self.handle.interruptWrite(XFPS.BULK_OUT_EP,msg,1000)
> print sent_bytes
> if sent_bytes:
> read_bytes = self.handle.interruptRead(0x81,sent_bytes);
> print read_bytes
>
> xfps = XFPS()
> xfps.open()
> xfps.my_bulk_write()
>
>
> Device info:
> ------------
>
> Full Speed device @ 3 (0x1D100000):
> ............................................. Composite device from
> Prolific Technology, Inc.
> Device Descriptor
> Descriptor Version Number: 0x0100
> Device Class: 0 (Composite)
> Device Subclass: 0
> Device Protocol: 0
> Device MaxPacketSize: 8
> Device VendorID/ProductID: 0x067B/0x0000 (Prolific
> Technology, Inc.)
> Device Version Number: 0x0000
> Number of Configurations: 1
> Manufacturer String: 1 "Prolific Technology Inc."
> Product String: 0 (none)
> Serial Number String: 0 (none)
> Configuration Descriptor
> Length (and contents): 39
> Raw Descriptor (hex) 0000: 09 02 27 00 01 01 00 A0 32
> 09 04 00 00 03 FF 00
> Raw Descriptor (hex) 0010: 00 00 07 05 81 03 01 00 01
> 07 05 02 02 40 00 00
> Raw Descriptor (hex) 0020: 07 05 83 02 40 00 00
> Number of Interfaces: 1
> Configuration Value: 1
> Attributes: 0xA0 (bus-powered, remote wakeup)
> MaxPower: 100 ma
> Interface #0 - Vendor-specific
> Alternate Setting 0
> Number of Endpoints 3
> Interface Class: 255 (Vendor-specific)
> Interface Subclass; 0 (Vendor-specific)
> Interface Protocol: 0
> Endpoint 0x81 - Interrupt Input
> Address: 0x81 (IN)
> Attributes: 0x03 (Interrupt no synchronization data
> endpoint)
> Max Packet Size: 1
> Polling Interval: 1 ms
> Endpoint 0x02 - Bulk Output
> Address: 0x02 (OUT)
> Attributes: 0x02 (Bulk no synchronization data endpoint)
> Max Packet Size: 64
> Polling Interval: 0 ms
> Endpoint 0x83 - Bulk Input
> Address: 0x83 (IN)
> Attributes: 0x02 (Bulk no synchronization data endpoint)
> Max Packet Size: 64
> Polling Interval: 0 ms
>
>
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