I'm getting different answers on various websites (Wiki, Online University courses, fan pages, etc...) and can't get to decide. That would mean there are SIM with Microprocessors and some with Microcontrollers? If so, which ISO or reference does it follow?
Thanks
A SIM Card is closer to a microcontroller than a microprocessor as it has all the required logic blocks including memory etc.
It differs from a microcontroller because it is a dedicated application circuit specifically designed with the security implications in mind. It is not a general purpose circuit like a microcontroller that can be used in many different types of applications (even if microcontrollers are more or less targeted to a field of applications). A microcontroller can not provide the level of security that a SIM Card provides.
It definitely is a microcontroller since it integrates a microprocessor, RAM memory, persistant memory, timers, I/O (7816 and optionally SPI, SWP, USB), security features and - often - a cryptoprocessor (DES, AES, ECC, RSA, hash). So both are correct: it uses a microcontroller, it uses a microprocessor. The applicable ISO standard is 7816 for smart cards. ETSI defines the SIM standards.
SIM cards are UICCs, which integrate a CPU, memory, and I/O on a single device. The relevant reference is ETSI TR 102 216.
