Hi Markus,

"Can i use the serial port of a 8051 to COMMUNICATE with the Card???".

Yes, sure you can. The ISO7816 standard defines a serial channel with one startbit, 8 databits and a parity bit, so you can use the 8051's UART in mode 3.

The bitrate is determined directly by the CLK frequency. After power-up/reset, the ATR will be sent at fCLK/372. With fCLK "around 4MHz" this means the bitrate will be "around" 10750 bps and you should set the UART accordingly.

Detecting the errorflag is a bit tricky; you will have to check the state of the I/O line 1 etu after the Receive interrupt. With a bitrate around 10k, this is not too difficult, but it gets harder when you want to use higher speeds.

Hope this helps.

Best regards,
Rob Klein.