Epidemic death of ST92F120

[sergio2]

Posted on December 09, 2004 at 12:15

Epidemic death of ST92F120

[sergio2]

Posted on May 17, 2011 at 11:34

We are experiencing a very high rate of problems with ST92F120V9Q7 with TraceCode A991Z0137Z from Malaysia

We are using these chips for an Automotive Application We sold the virgin chips on the board, and then, we record them the program with a ST92F120-EPB via ISP. We don't use the E3Prom, we don't use an external Watchdog and at the address 0x000006 we place a 0xFFFF After some days of working correctly, the ST92F120, suddenly stops to work The chip behaves as in Reset Status, or as didn't have any program in the Flash When we try to record the Flash via ISP again, we have an eror ''No comunnication with device'' The only solution is then to replace the ST92F120 The power comsumption of our Board is: Normal: w/Virgin flash=18 mA - w/reset low=18 mA - Running w/reset Hi=50 mA After Malfunction W/Reset Low=18 mA - w/reset Hi=18 Ma (without vital signs) Which the workaround should be, to find and to solve the cause of the problem? Thanks for your help

[loic2]

Posted on May 17, 2011 at 11:34

When you try to program the Flash again via ISP, you have an error ''No comunnication with device''. Did you try to read/verify the flash via ISP ? IN this case, go you get the same error message?

Do you still have any clock signal on oscin/oscout?

[sergio2]

Posted on May 17, 2011 at 11:34

In fact I cannot make any task via ISP (until the chip replacement), since the F120 doesn't communicate with the EPB again (it is as if was permanently at reset status or is dead)

The oscillator is external and we have normal oscillation on the OscIn/OscOut pins

[ritu]

Posted on May 17, 2011 at 11:34

After removing the damaged device from the board have you tried to read it directly on EPB (Without ISP mode).or have you just tried to check for clock at oscout/ oscin pin using quartz b'coz if the device becomes actually dead after sometimes then we should not even see the clock with crystal. (On chip clock circuitry is required to have clock on oscout and oscin pin). And for device getting permanently damaged the only reasons can be if we exceed voltage or temp. limits. May be somwhere in your circuit you have a transitory spike of very high voltage. which damages the device completely and after you don't see any abnormal power consumption. or may be you can just try to run all the IP's which you are using in u'r application in their respective modes indepenently on the device and see if it gets damaged over a period of time it might help in locating the source of problem.

[sergio2]

Posted on May 17, 2011 at 11:34

Thank you Ritu for your suggestions

We prove to place a quatz directly in oscin and oscout (on a defective ST92f120 chip) and we obtained normal oscillation in those pins We don't believe that, after remove the chip from the board, the unsoldered pins allows a reliable contact inside the EPB's socket to make reasonable tests. We don't believe that it is a problem of exceeding the chip's absolute maximum ratings, since we overvoltage protection, and we are using the same power supply that we also used in a previous equipment also for automotive that uses a ST90T40, with which, we have never experienced these problems

[tprohaszka]

Posted on May 17, 2011 at 11:34

Did you ever find the issue with the dead parts? We are finding a similar problem with an F150.

[sergio2]

Posted on May 17, 2011 at 11:34

Please, look at the attached document

Replacing the pieces ''Z'' with the pieces ''Y'' the problem didn't happen more