The problem of flash data rewriting after IC S9S12ZVL does unpowered ESD

[congcongpan]

    IC S9S12ZVL32FOMLF LQFP-48 does unpowered ESD,the Flash data is rewritten，The data is shown in the figure below，red is abnormal code, green is normal code, all are read from IC.

    After the circuit board is powered on for about 10 minutes, the PWM output waveform of one channel of the IC is abnormal.

    Why Unpowered ESD causes this phenomenon? Can flash not be rewritten through software enhancement.

[dianabatrlova]

Hello,

Could you, please, describe your ESD test and provide more information about PWM?

Thank you.

Best regards,

Diana

[congcongpan]

Hi Diana:

      The sample is not connected to the harness for unpowered ESD test. For the + 15kV air discharge of metal parts, after the discharge, we use CodeWarrior to read the internal code of the chip and compare it。After that, we find different code problems.

      The PWM output is normal at the time of power on, and the waveform is abnormal about 10 minutes later.

                   Figure1  Before the ESD test                            Figure2  After the ESD test

        When we rebuild the program to IC, everything is back to normal. Now we can be sure that the flash code has been changed when there is electrostatic interference, it is near the chip。

Thank you.

Best regards,

Pete

[dianabatrlova]

Hi Pete,

I have discussed your case with application engineers and we need more details, see below.

If you cannot share it publicly you can create a support ticket:

Support | NXP 

Please could you provide more info related to the next topics:

• Parameters of the ESD Test.
• Full Schematic and PCB layout.
• Source code of the test.
• The debugger remain connected during the test? Which debugger is used?
• Could you perform the same test for 10 minutes without applying the ESD discharges, is it still behaving correctly?
• The "abnormal" change always occurs in the same address and number of bytes.
• Could you add a byte array before the main function only to move the address of these functions?
  • Something like this:

    uint32_t my_Array[] = { 0xffbbff0b, 0xfdad974d, 0xa9662905, 0xaefdef82 };

    We could expect to see the problem in the same place.

We must ensure that you do not exceed the parameters of the device, outside of this we cannot guarantee its operation.

Thank you.

Best regards,

Diana

[congcongpan · Accepted solution]

Hi Diana:

       I'm sorry that I can't provide relevant data. We have tried our best to solve this case. It should be because the chip is too close to the metal screw hole.We have carried out the optimization from the design, and no similar phenomenon has been found in the current test, It should be the data directly caused by electrostatic changes.

      After our rectification, everything is normal.Thank you very much for your help.

Thank you.

Best regards,

Pete