How to write MPI/USB driver for S7 mpi/usb adapter?

[chenhg]

Does anyone has written usb driver for S7 mpi/usb adapter(6ES7972 0CB20 0XA0).We want to do this.(OS:windoexp,VC6.0++)
We have found the adapter device (VID_0908 & PID_0004)using general usb driver.We then Createfile()successfully.We send(call function writefile()) the mpi first byte(0x02) to PLC,then start a read thread to read msg (call function readfile()),PC came to bluescreen,read failed.

Any comments for me? Appreciate any help.

 

[chenhg]

It's ok

The ReadFile() problem has been solved by changing the receiving or sending buffer.My COM default size is2048.When I set 256,the driver runs well.So I can only set the datablock address length to be 210.
The speed of communication is 100ms/210 bytes by MPI/USB cable.
As a doubt, Why I can't set the buffer size to be 2048?
Thanks anyone anyway.

 

[toostablo]

Hi
What`s part number ic ( chip )usb controller of simatic usb adapter?