Hi

There are two ways.

The first is easier. Use the 8051 serial port. Use 2 analog switches (4066) to combine TX and RX to become the cards I/O line. If you use a 3.58MHz crystal on the 8051 then feed the crystal clock output to the clk pin of the smart card. Use a port pin for reset and to control the data direction of the serial port. Remember to use Even parity in the serial port setup. BAUD rate = 9600. (clk / 372)

This solution will not give you byte by byte error detection and retransmission unless you can code it somehow.

Too achieve this use the second method.

The second method is to use a single port pin and write your own software UART.

Error detection can be done on the packet/frame level using LRC(XOR)/CRC's

Beyond ATR you will need ISO-7816-3/4 specs and more.

There are MCU's that support smart card interfaces, H8S2245(Hitachi) and Mitsubishi. I don't know of any 8051's, if anybody does let us know.

Good luck

Andre