> I found in my design, PSoC4200 is very easy to be burned.
I'm very sorry for hearing that.
> Sometimes if short power to GND carelessly,
> there would see spark and smoke from PSoC chip.
I hope that most of EE students are taught to power off the circuit when wiring.
And the hardware engineers I have known usually measure the resistance between VDD and GND before powering the circuit.
Sometimes a device can cost more than a brand new car or more.
> I'm think it is burned due to the over current?
Probably that was the reason besides some circuit shorts.
> I didn't add fuse on power line.
Nor do I usually.
One thing I noticed recently is if I'm providing power from PC's USB,
the circuit gets shut off when the USB circuit detects the overload.
I often forget a resistor for LED and overload the circuit, but have been saved by this.
So I'm very sorry for the tragedy,
but IMHO, we can burn almost any device and it's not only PSoC 4200.