Difference performance between Windows 2000/Windows NT Operation System about Serial Commuincation for downloading data to Mobile Phone Using RS232 Interface, and Does LabWindows-CVI support USB Interface Programming

[lambert]

Hi, all
Question 1:

Recently, I developed an aplication to download the data to the mobile phone, and developed in Windows 2000 OS using LabWindiws-CVI 5.5.
This application is running as following steps:
1. PC <-> MS communication with baudrate 38400, 8 bits, even parity, and 1 stop bit.
2. Turn on the MS, the PC get the handshake byte and write the bootstrap loader the Ram of the MS.
3. Change the baudrate from 38400 to 115200 with the same data settings.
4. Bootstrap Loader running, and read the data from the PC file and write
the data to the Flash of MS.
5. Finish the data downloading.
In the Windows 2000, the performance of this application is ok. But for the Windows NT 4.0, it is fail in the Step 2 or 3.
Because the download processing is critical for timing.
I also try to run in the Windows ME, it is fail, too.
For Windows 98, it seems to be unstable for download processing.

Does there have any difference among Windows 2000, Windows NT 4.0, Windows ME and Windows 98 for the lower level programming on the RS232 interface.

Question 2:
Does LabWindows-CVI support USB control programming to access USB interface?

If you have any suggestion about it, please tell me.

Best Regards,

Lambert Lin

[Elaine_R.]

hello Lambert -

In general National Instruments products don't offer any native USB support, CVI and labVIEW will communicate with your USB devices based on the specific driver involved, USB does not use the same serial protocols as RS232 so these libraries will not have the results I think you are expecting.

As to the odd behavior you're seeing when you port your Win2000 code to the NT box, what sort of unstable behavior are you seeing? Are errors/warnings being generated? Is it blue-screening? Can you trace which functions or opperations seem to be causing the trouble? If this is a time-out related problem you may want to investigate using the SDK toolkit for setComRate or simlar RS232 handling functions, there is a discussion of this on another Developer's Zon
e question called "How Can I configure the RS232 baud-rate?" where detail on the problem is given. A good place to start debugging this behavior would be to see if the Serial examples in CVI exibit similar issues. If the problems persist even with the tutorials or with simplified code, please submit the exact error to either the forums, or to the email support engineers at http://www.ni.com/ask.

Good Luck,

Elaine R.
National Instruments
Applications Engineer
http://www.ni.com/ask