I have a keypad, 3 rows, 4 columns, my rows are connected to PortB bits 1-3, the columns are connected to PortB bits 4-7. I set PortB.0 to 1 (high) feeding four 1n4148 diodes anode to PortB.0 cathodes to bit 4-7. When a button is pressed on the keypad it pulls whichever pin 4-7 low. I have OPTION_REG.6 = 0 to trigger on the falling edge.


Thanks