In article <3344906E.4978@topher.net>, dragon writes >been doing basic i/o with 16f84 " if input do output " >but i now need to be able to scan a 4 x 4 keypad and get >1 and 2 key inputs from it. Any suggestions or pointers >would be greatly appreciated. It's quite easy. I've done it with an 8 x 8 matrix on the 16C74. You can use one port as column outputs, and the other as row inputs. You ripple the active column line along (one column going high at a time) and read the input port for that column and see what rows are high. You need diodes in series with the switches, column anode to row cathode - so that a switch down in one column won't short out a switch in another column (same row) that hasn't been read yet. Jim -- Jim Main