[pyusb-users] ctrl_transfer problems about PYUSB

[4. <442...@qq...>]

Hi,
    In these days I am working on pyusb to establish a connection between my laptop(Windows 7) and one FX3 hardware.
The first thing I must do is to download the firmware,but I met some problems.The downloading process is easy to describe,and I am sure about the .img data is writen to FX3 RAM by BUS HOUND tool,but the problem appear in the last step.When I try to use ctrl_transfer() function to execute to Program Entry,it failed.So I can't finish my download.I have tried several ways to send one zero length control transfer,but got the same I/O error message on the screen. I tried it as follows:
dev.ctrl_transfer(0x40,0xa0,addr_l,addr_h)
or  dev.ctrl_transfer(0x40,0xa0,addr_l,addr_h,None)  or dev.ctrl_transfer(0x40,0xa0,addr_l,addr_h,None,500)


Have you met this problem?Can you help me to solve this?Thank you very much!