Robert Hamilton

Possible Bug in ZSTAR Demo's Virtual Serial Port Driver

Discussion created by Robert Hamilton on Sep 14, 2007
Latest reply on Mar 5, 2009 by Martin van den Berg

Possible Bug in ZSTAR Demo's Virtual Serial Port Driver


Our ZSTAR project has been stalled by an apparent bug in the ZSTAR Demo's Virtual Serial Port driver; hopefully someone here may be able to shed some light on this problem.

For several months we've been attempting to integrate the ZSTAR in the design of a new product. Suddenly, the ZSTAR Demo's Virtual Serial Port driver has stopped working. This failure had already occurred on several previous occasions, yet we had always been able to restore the driver's functionality by going to a Windows restore point, or by reinstalling the ZSTAR driver SEVERAL TIMES. Unfortunately,with this most recent driver failure, no amount of driver re-installs, nor anything else has restored functionality. THE DRIVER SEEMS TO BE PERMANENTLY BROKEN.

Here are some pertinent points:

1.We conclude that the ZSTAR's Virtual Serial Port driver has failed because whenever the Visual C++ GUI app RD3152MMA7260Q_SW.exe was run, and the appropriate com port selected, the program COULD NOT CONNECT to the ZSTAR Demo, and the following error was reported: "Please check the battery & serial cable then power down & power up your Triax Board. ATTEMPT #1/5 Character 5".

2.During all such failures of the Virtual Serial Port driver (as referenced above), no ZSTAR handshake request was successful from within Hyperterminal—as would be expected. Yet at the same time the Windows Device Manager claimed the Com Port WAS present, identified the connected device as the Triaxial ZSTAR, and reported that the com device was working properly. This in itself seems peculiar!

3.During all failures of the Virtual Serial Port driver, the ZSTAR mouse driver could still be successfully invoked.

4.All failures of the Virtual Serial Port driver were preceded by extended periods of time during which the Virtual Serial Port driver had worked as intended.

5.The Virtual Serial Port driver finally failed PERMANENTLY on a computer that was running Windows XP-SP2, our development platform. In order to see if the ZSTAR hardware itself were malfunctioning, we installed the ZSTAR drivers on another computer, which was running Windows Vista. All the original ZSTAR hardware and software worked fine on the new system. So, the ZSTAR hardware is not broken.


6.For various reasons we NEED to run the ZSTAR on our original XP system. Consequently, for the time being, our project is on hold.



Two questions for you: One--do you have any suggestions as to what might be causing this problem, and of course how to remedy it? Two--have others reported any similar problems with the ZSTAR Demo's Virtual Serial Port driver? Our search of the Freescale forums has turned up nothing.

We have considered just putting everything on another XP system, but how do we know that the same driver problem won't pop up in the future on the replacement computer?

The problem seems to be some sort of driver instability. At the very least, the driver is exhibiting inconsistent and unreliable behavior. We are considering the possibility that this driver problem may have its origin in the Windows registry, but so far we have not come up with anything definitive.

In passing, I might mention that we have tested many other pieces of software and hardware on the very same XP development platform that we are now using for our new ZSTAR project. Yet this ZSTAR Virtual Serial Port driver glitch is the first instance of any such problem.

Any help you can render would be greatly appreciated. Thank you for your attention,

Robert Hamilton

Design Engineer