Hi All,
I'm currently working on the device side function driver development for TMC gadgets.
Based on my experience and reference from USBTMC Specification as well as a couple of example code from Google, I have developed this driver.
Now I have one weird problem with my above USB TMC function driver, It works fine under Linux host but not in case of Windows host.
Case-1: Linux as host.
1) On embedded board load the g_tmc driver and it creates /dev/g_tmc0 device node.
2) Make a connection between Linux host and embedded Linux board.
3) On the Host side(Ubuntu 16.04), usbtmc class driver load automatically and /dev/usbtmc0 is also created well.
4) Command string also I can send from Linux host side like
echo *IDN? > /dev/usbtmc0
5) on the device side /dev/g_tmc0 device file also give me a perfect output.
I have attached snap for the same as tmc_read.png
Case-2: Windows 7/10 as Host
1) On embedded board load the g_tmc driver and it create /dev/g_tmc0 device node.
2) Make a connection between Windows 7/10 host and embedded Linux board.
3) NI-VISA / IVI Shared component successfully detect my tmc gadget and I can see the device in my DEVICE MANAGER under Test & Measurement Class category.
4) Now If I run an example from Users/Public/Documents/National Instruments/NI-VISA/Examples/C/USB path of NI-VISA then viOpen and viFindRsrc function failed to open and find my device.
Questions:-
Why is behaviour not same under the two different host?
Why Windows 7/10 can detect my tmc gadget but NI-VISA fail to make a connection?
What is the different between usbtmc class driver of vanilla Linux and NI VISA usbtmc driver?
