Home › Forums › Microcontrollers › PIC Microcontroller › 18F4550 with 74LS138 › Reply To: 18F4550 with 74LS138 June 11, 2015 at 8:30 am #11471 Ligo GeorgeKeymaster You may use it like matrix keypad. Use 6 pins of PIC as inputs such that you can connect 24 x 6 = 144 switches.
