Hi,
Let me provide some background on the problem:
- Vdd is 3.1V
- To save power, the microcontroller (µC) is put in sleep mode.
- To wake it up, we change the state of a GPIO pin using an external signal, which we'll call S_ext.
- Sometimes we detect that the voltage of S_ext is greater than Vcc+0.3.
According to the datasheet, the amplitude of the signal going into the GPIO should not be greater than Vcc+0.3V. However, our product still seems to be working.
I have some questions:
- If the condition Vcc+0.3 is not met, can the µC still be functional? What are the risks?
- Is the only risk that the pin's ESD protection might be broken? Our product is resin-coated to avoid ESD issues. Is that why it's still working after applying a signal greater than Vcc+0.3V to the pin?
- What will happen if the voltage applied to the pin is more than 4.1V?
Thank you in advance
Best regards
Liang
