The ST72321BAR9 has been discontinued for a long time and is no longer available, but there is still a little information (datasheet, application notes etc) on the website.
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Is there any other Microcontroller that supports USB-CCID protocol ? If more than one, then can you post a list of these microcontrollers in the order of increasing no. of GPIO pins.
If you want to implement CCID via USB, there are a very large number of STM32 with USB that can cover this. The list is too long to include here. Maybe it would be helpful if you contact your nearest distributor for help?