Before, I asked some ways to solve the EMI problem and I got some useful answer from here: Really occasional malfunction of the Schmitt-trigger input - Really occasional malfunction of the Schmitt-trigger input However, another problem has risen.
My board has some adjacent LEDs near the 'trouble making area', and I revealed that sometimes they are powered off by my hand(Of course, I didn't touch the LEDs, I just brought my hand near the lights). For the 74HC14 problem, I added some capacitors to reduce the effect of the EMI and that was really successful. But, what can I do for these LEDs? LEDs are just connected by the MCU output pin, series connection with a resistor. For example, the part of the LED circuit will be MCU PIN->Resistor->LED->GND.
Ironically, this output pin indicates whether the network is on or off and even if the LED is off, the WiFi chip keeps connected to the server. So I think it is just output-related issue.
Would just adding some capacitors near the output pin going to GND be okay? If this is applicable, could I apply to similar situation?
- This is the part of the circuit. The board is perforated and there are so many adjacent connections(especially for 74HC14, near the LED).
These are somewhat more general circuit(showing nearly located circuits).