Programming a remembered Passcode for a PIC16F88

Discussion in 'Embedded Systems and Microcontrollers' started by Baleak, Nov 14, 2010.

  1. Baleak

    Thread Starter New Member

    Nov 14, 2010
    I am trying to program an user input password (4 digits) that a PIC16F88 will remember(even when powered down). I was wondering if anyone had any ideas on where to start. I am thinking about setting 4 different variables using
    J Var byte
    but I'm not sure if this data would be reset when the system powers down.
  2. AlexR

    Well-Known Member

    Jan 16, 2008
    I have no idea what a "J Var byte" is or even what programming language it refers to but I would have thought that the obvious way to store a password so that it would not be lost on power down would be to write it to EEPROM.
  3. maxpower097

    Well-Known Member

    Feb 20, 2009
    I've done this already. Basically heres what we did.
    1. Set bit's to check at boot to see if a password has been set up.
    2. If not then ask to set up a password.
    3. If so then proceed to boot normally.
    4. Enter a lock on the main menu asking for a passcode to enter menu area
    5. Let user set PIN at first boot or in menu.
    6. If they set the passcode up in menu it activates and locks everyone without the passcode out. We stored the setup bits, and passcode on the PIC16LF877A's internal epprom.
    If you can't figure it out I'll dig through my old code and try to find you snippets. Its all in ASM and is a huge program, around 4,500 lines. So it's not gonna be easy to just find all the password stuff.
  4. Tahmid

    Active Member

    Jul 2, 2008
    I think you're using PIC Basic compiler, right?

    maxpower097 has suggested a good method.