prepaid energy meter

Dear all,
im trying to design a a single phase prepaid energy meter using ade7569 ic manufactured by Analog. i had succeded in building the meter but i cant move to the second stage which is the prepayment, my question is '' how to connect a smart card ic to ade7569 ic to acheive the prepayment? can the connection be direct or through another mcu and what is the best smart card for such a project? im welcoming all answers and suggestions
Best regard

we never go by the smart card and we are drive this pre paid using mobile.