interface keypad 4x4 with PIC16F876A

Discussion in 'The Projects Forum' started by ayiemaru, Oct 21, 2012.

  1. ayiemaru

    Thread Starter New Member

    Oct 19, 2012
    0 in doing a schemati for RFID door lock plus password..i dont know how to interface keypad with my PIC..please help me about their pin..
  2. SPQR


    Nov 4, 2011
    Perhaps some details might be in order?

    Type of keypad?
    Type of PIC?
  3. Dodgydave

    Distinguished Member

    Jun 22, 2012
    a 4X4 Keypad scanning uses a full 8 bit port, 4 rows by 4 columns.

    So if bits 0-3 are the columns and bits 4-7 are the rows, you make bit 0 high then scan 4-7 to see if a bit has changed state, then make bit 0 low and bit 1high and scan bits 4-7 again, repeat for bits 2&3,

    so your programme would make bits 0-3 outputs and bits 4-7 inputs, a total of 16 keys scanned.