How to tackle keypad RF immunity problem?

[artem]

Hello

RF modem based design includes keypad and connection between keypad to pcb is done by 10-20 cm wires. To reduce costs keypad scan is done by microcontroller directly. Due to rf modem operates something around 900 MHz there could be problem with rf immunity of microcontroller inputs . Of course it is possible to use ferrite beads or chip resistors together with capacitors to form LF filter on gpio inputs, but I am interrested to know if there are other ways to overcome situation? There is dedicated ground layer on pcb, and keypad wires are not shielded.

thanks in advance

 

[spikeyang]

Keypad RF immunity

Pls use connector with the keypad, or keep wires as short as possible,away from the antenna as far as possible.Some shielding is preferrable.


The long wires between will dedicately demodulate the burst shape of the GSM900 MHz signal.(I guess it's GSM u r using)