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Graham edited this page Mar 18, 2017 · 1 revision

Making Contact

The tutorial boilerplate seems to work...

DEVICE ID 054c:0034 on Bus 020 Address 012 =================
 bLength                :   0x12 (18 bytes)
 bDescriptorType        :    0x1 Device
 bcdUSB                 :  0x110 USB 1.1
 bDeviceClass           :   0xff Vendor-specific
 bDeviceSubClass        :    0x0
 bDeviceProtocol        :    0x0
 bMaxPacketSize0        :   0x40 (64 bytes)
 idVendor               : 0x054c
 idProduct              : 0x0034
 bcdDevice              :  0x100 Device 1.0
 iManufacturer          :    0x1 xxxx
 iProduct               :    0x2 PCLK-MN10
 iSerialNumber          :    0x0 
 bNumConfigurations     :    0x1
  CONFIGURATION 1: 100 mA ==================================
   bLength              :    0x9 (9 bytes)
   bDescriptorType      :    0x2 Configuration
   wTotalLength         :   0x20 (32 bytes)
   bNumInterfaces       :    0x1
   bConfigurationValue  :    0x1
   iConfiguration       :    0x2 PCLK-MN10
   bmAttributes         :   0x80 Bus Powered
   bMaxPower            :   0x32 (100 mA)
    INTERFACE 0: Reserved ==================================
     bLength            :    0x9 (9 bytes)
     bDescriptorType    :    0x4 Interface
     bInterfaceNumber   :    0x0
     bAlternateSetting  :    0x0
     bNumEndpoints      :    0x2
     bInterfaceClass    :    0x0 Reserved
     bInterfaceSubClass :    0x0
     bInterfaceProtocol :    0x0
     iInterface         :    0x0 
      ENDPOINT 0x1: Bulk OUT ===============================
       bLength          :    0x7 (7 bytes)
       bDescriptorType  :    0x5 Endpoint
       bEndpointAddress :    0x1 OUT
       bmAttributes     :    0x2 Bulk
       wMaxPacketSize   :   0x40 (64 bytes)
       bInterval        :    0x0
      ENDPOINT 0x82: Bulk IN ===============================
       bLength          :    0x7 (7 bytes)
       bDescriptorType  :    0x5 Endpoint
       bEndpointAddress :   0x82 IN
       bmAttributes     :    0x2 Bulk
       wMaxPacketSize   :   0x40 (64 bytes)
       bInterval        :    0x0

A short anecdote about setting up.

We were going to attempt to figure out control commands but that was unneeded. The windows driver (and this library) send something (very close to):

# SETUP PACKET:
#    80 06 00 01 00 00 12 00
>>> dev.ctrl_transfer(0x80, 0x06, 0x0100, 0, 0x12)
array('B', [18, 1, 16, 1, 255, 0, 0, 64, 76, 5, 52, 0, 0, 1, 1, 2, 0, 1])
# SETUP PACKET:
#   80 06 00 02 00 00 09 02
>>> dev.ctrl_transfer(0x80, 0x06, 0x0002, 0, 0x0902)
array('B', [9, 2, 32, 0, 1, 1, 2, 128, 50, 9, 4, 0, 0, 2, 0, 0, 0, 0, 7, 5, 1, 2, 64, 0, 0, 7, 5, 130, 2, 64, 0, 0])

After many attempts, finally a write/read seemed to do something -- just the once...

>>> ep.write([0x00,0x60,0x00])
3
>>> rep.read(40)
array('B', [0, 96, 17, 0, 100])
>>> ep.write([0x00,0x60,0x00])
3
>>> rep.read(40)
array('B')

It transpired that the device had become confused somehow; a replug determined that this was indeed the poweron command. It seems that sending lots of garbage (or failing to read at appropriate times?) might cause something to get confused / out of sync somehow.

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