pic chips and smartcards!! help please ;)

Discussion in 'Embedded Systems and Microcontrollers' started by totalacedude, Jan 19, 2011.

  1. totalacedude

    Thread Starter New Member

    Jan 19, 2011
    hi guys,

    im trying to make a code lock using a simple smartcard, im looking to use something called a 'goldcard' its a smartcard that has a pic 16f84a and a 2k eprom inside.

    basically i have seen programs that i can take bits out of to make it do what i want, but more to the point i want to understand how it works!

    it uses the standard iso 7816 protocol


    what im trying to understand is if you look at the picture the pins that connect form the reader to the 16f84a are the clock reset and data, but the clock goes to the clock pin on the pic micro.

    knowing that every line of code in a the processor takes 2 clock pulse to fetch and excequte how does the pic inside the card read the data coming to and from the master while only being clocked at the same frequency, ie not only does it read it it also has to do other things likemove it to different regesters etc.

    ie i would have expected the osc1 pin to be clocked alot higher than the speed of the clock from the reader so it gives it time to do things with it before the next clock pulse from the reader....?

    well confused....

    is there something special being done with the clock osc1 input???

    cheers ian
  2. beenthere

    Retired Moderator

    Apr 20, 2004
    If I had to guess, I might think that the ins and outs of programming smartcards are not going to be in the public domain. Otherwise, how does the data on the card remain secure?