Something curious is happening with my USB HID device.
It is a Full-speed Device. The curious thing is that my VB software transfers 64 bytes of data (EP0 CONTROL TRANSFER) to the device only one time each 05 SOF signals of the USB line. So, instead of 64 KB/s I am only having 64/5 Kb/s data transfer rate.
I have even set my VB software to run in High priority mode - So it has nothing to do with Windows priorities.
Would anyone have a clue how I can increase the data transfer rate ?
Yes It really worked !!!
Everything is fine. I am finding a problem in the READFILE function, though. I think you´ll know the answer.
Supose the device sends an IN PACKET. If I run the ReadFile function AFTER the packet has arrived to the Host, the function gets back with the correct result.
In the other hand, if I make a loop for the readffile function to detect the arrival of a packet, it never finds it the loop goes on forever.
How can I make the readFile function detect the packet while in the loop ?
Please find below the loop I am using in VB6
While (NumberOfBytesRead < 64) recv_buf(0) = 1 result = ReadFile(ReadHandle, recv_buf(0), CLng(Capabilities.InputReportByteLength), NumberOfBytesRead, HIDOverlapped) DoEvents Wend
Thanks
Antonio
Just to add to the above post.
If I us the createFile function without the FILE_FLAG_OVERLAPPED The readfile detects the in Packet without a problem.
But I need to use the FILE_FLAG_OVERLAPPED because I need the function to return and not hang the thread until the packet arrives. what to do ?
This one doesn´t work 'ReadHandle = CreateFile _ (DevicePathName, _ (GENERIC_READ Or GENERIC_WRITE), _ (FILE_SHARE_READ Or FILE_SHARE_WRITE), _ Security, _ OPEN_EXISTING, _ FILE_FLAG_OVERLAPPED, _ 0)
This one works but the thread hangs untill the packet arrives 'O PACOTE F0 QUANDO O VB ESPERA EM LOOP ... ReadHandle = CreateFile _ (DevicePathName, _ (GENERIC_READ Or GENERIC_WRITE), _ (FILE_SHARE_READ Or FILE_SHARE_WRITE), _ Security, _ OPEN_EXISTING, _ 0, _ 0)
I made it work.
Everything works perfectly now.
For HID programming on PC side in VB.Net, this library make your life easy. When you don't use it directly, the source code will give you many suggestions.
USB Hid Device Library " href= "http://www.lvr.com/hidpage.htm">http://www.lvr.com/hidpage.htm www.lvr.com/.../generic_hid_vb_46.zip
Tsuneo
HI, Tsuneo,
Something funny is happening with my VB application that controls the HID device.
When I run the software fom within the visual studio 6, it works fine and talks to the device, both in XP and windows 7.
After compilation, the .exe runs OK in wondows 7, but not in XP. In XP it issues no errors, but does not send messages to the HID Device.
It seems to me it is something abou the registration of the .dll in wondows. I am using the VB code from JAN AXELSON so I have tried to register (Using regsvr32) the .OCX and .DLL. The HID.DLL and setupapi.DLL isues and error (Entry point not found) and does not register.
Have you ever experienced anything like that ?
Maybe, your distribution is missing some DLL (or OCX) required.
Run Dependency Walker on the target PC for your application EXE. It tells missing DLL, if any.
Dependency Walker www.dependencywalker.com/
See VB6 manual at the chapter of packaging for deployment, to make setup project.
Distributing Your Applications - VB6 msdn.microsoft.com/.../aa716256(VS.60).aspx