We have developed a design with mc9s12dg256 controller, but we have severe problems with electrostatic discharge.
We apply 8KV air discharge on vertical metal surface (PCB board is 10cm away from the metal surface). After several air discharges controller resets.
This is not happen in regular times; sometimes controller resets after 2 or 3 air discharges and sometimes controller resets after 10 or 12 air discharges.
The design is very simple; it is a double layer PCB with mc9s12dg256 controller, a voltage regulator, a reset circuit and pull down registers on each IO port.
I have attached schematic and PCB.
Could anyone tell us if there is any error in our design?
We will appreciate any help