Part Number: MSP430FR2675
Hi experts,
Currently my customer has created a prototype board using MSP430FR2675, but occasionally malfunctions occur with the input of the electrostatic sensor.
The phenomenon: they are using the electrostatic sensor as a touch switch and there are 4 electrostatic switches. Touching the switches changes the mode of the user product. But occasionally, after changing the mode, all the electrodes respond even though the switch is not touched. (4 electrode switches reacting at the same time)
Detailed situation: This time, on the MSP430 side, only the function of the electrostatic sensor and the GPIO are working.(and UART for DesignCenter)
- When power is turned on, the device is in Mode0 and all three GPIOs are in Low state.
- By pressing SW1, it changes to Mode1 and changes the combination of the three GPIOs at the same time. (H,H,L)
- By pressing SW2, it changes to Mode2 and changes the combination of 3 GPIOs at the same time. (H,H,H)
Normally, after changing to Mode2, each electrode switch will respond normally. However, sometimes, after changing to Mode2, all the electrode switches respond. (They confirmed in DesignCenter that all electrodes have equal capacitance change.) It takes about 5 seconds for all 4 to be pressed.(There is no finger near the control SW.) Pressing SW1 turns off the power and returns to Mode0. The moment the product enters Mode2 on the product side, the amount of current changes, and it appears to be occurring at that time.
Question: After pressing a capacitive touch switch like this one, is there a pattern where the capacitance is affected at the same time? Or have you seen similar cases in the past?
There is a possibility that this is a customer's board (hardware) factor, so we are continuing to verify this, but any insight or information from TI would be appreciated.
Best regards,
O.H
