I have an FPGA demo board and on the GPIO I have attached a 4 x 3 membrane keypad. This keypad is simple, create a current on the column pins and look for a completed circuit on the row pins.
At the minute, I just having it driving a bunch of LEDs to indicate what has been pressed. I have written the VHDL code for this and it appears to be working fine.
My problem is that if I bring my hand within 15cm of the keypad, the LEDs start to light up. So, I am coupling with the circuit and bridging the switches. I dropped the frequency from 2MHz to 1KHz to try to resolve it, but no luck. I can move my hand around the keypad and cause different LEDs to light up.
Does anyone have a resolution for me?
At the minute, I just having it driving a bunch of LEDs to indicate what has been pressed. I have written the VHDL code for this and it appears to be working fine.
My problem is that if I bring my hand within 15cm of the keypad, the LEDs start to light up. So, I am coupling with the circuit and bridging the switches. I dropped the frequency from 2MHz to 1KHz to try to resolve it, but no luck. I can move my hand around the keypad and cause different LEDs to light up.
Does anyone have a resolution for me?
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