Enhanced performance 16-Bit secure MCUs are five times faster for smart cards such as credit/debit and ID cards

The RS-4 Series of 16-bit secure MCUs is the successor to the AE-4 Series of 16-bit secure MCUs, which has a solid track record. The RS-4 Series maintains CPU instruction code compatibility with its predecessor while delivering approximately five times*2 the processing performance. This increased processing power enables the RS-4 Series to handle tasks that were beyond the AE-4 Series and would previously have required developers to employ a 32-bit Renesas MCU. The new secure MCUs can perform complex processing at high speed, making it possible for them to run a multi-application OS (such as Java Card™*3 or MULTOS*4 ) faster, which is necessary to implement multiple functions on a single smart card. In addition, the low-power design makes it suitable for non-contact type operation. The RS-4 Series enables developers to realise contact-type or non-contact type smart cards offering high performance and multifunctionality using a 16-bit MCU.

Regarding the security aspect, the RS-4 series implements encryption processing, required in the financial field, based on that of the AE-4 Series. In addition, the RS-4 Series adds a coprocessor supporting stronger AES (Advanced Encryption Standard) encryption and other security features. The final product versions will offer smart card MCU security level EAL5+*5 certification as defined under the latest version of the Common Criteria for IT Security Evaluation an attestation of high-level security demanded by the target market.

The RS-4 CPU core of the new RS-4 Series employs a proprietary Renesas architecture that has been newly developed for use in secure MCUs. It has a 16-bit arithmetic unit and a 16-bit internal bus. The RS-4 CPU core supports the entire instruction set of the earlier Renesas AE-4 16-bit CPU core for code-level compatibility. This means that software resources developed for the AE-4 Series can be reused with the RS-4 Series, reducing the time and cost required for system development. Compared with the AE-4 Series, the RS-4 Series is designed to deliver better performance, enhanced security, and additional peripheral functions for improved flexibility. The features of the RS-4 Series are summarised below.

1) Five times the processing performance of its predecessor for the fastest operation possible by a 16-bit MCU when running a sophisticated multi-application OS.
The minimum time required by the RS-4 16-bit CPU to execute one instruction is one clock cycle. Compared with the earlier AE-4 16-bit CPU, which needs two cycles per instruction, the RS-4 Series is twice as fast when operating at the same clock frequency. Furthermore, the RS-4 is not dependent on an external clock by having an internal clock oscillator as one of its new peripheral functions, and achieves the maximum internal operating frequency of 20MHz. The overall result of these improvements is approximately five times*2 the processing performance of the AE-4 series. This extra power enables the RS-4 Series to handle the complex processing load of a multi-application OS such as Java Card™ or MULTOS™ faster. This was not possible with the AE-4 Series and would have required the 32-bit AE-5 Series. Finally, the low power design of the RS-4 Series makes it suitable for use in non-contact type smart cards, which the 32-bit AE-5 Series does not support. The RS-4 Series can be used in both contact and contactless smart cards.

2) Advanced encryption processing.
The encryption processing functions of the new RS-4 Series are implemented by a powerful modular multiplication coprocessor supporting, for example, RSA encryption and a triple DES (Data Encryption Standard) coprocessor that improves on the previous DES coprocessor. There is also a new coprocessor with support for AES, an encryption standard that is gaining attention as a successor to DES. The RS-4 Series can process a variety of types of encryption operations at high speed.

Other peripheral functions that contribute to enhanced security include: a new pseudo random sequence generator for generating random numbers at high speed as an effective security measure; and incorporation of the latest security technology for protecting against light attacks. As a result, the final product versions will offer smart card MCU security level EAL5+ certification as defined under Common Criteria for IT Security Evaluation, an attestation of high-level security demanded by the target market.

As a development tool, sample shipments have begun of an emulator*7 with the first RS-4 Series logic chip product installed on it. This will enable developers to start creating and evaluating software before sample shipments begin in the second quarter of 2008 (April to June).

The standard Renesas development environment, High-performance Embedded Workshop, is the user interface for the development tool. It will allow developers to create and debug programs efficiently using an interface they are already familiar with.

Typical applications are smart cards: ATM cards, credit cards, prepaid cards, e-money cards, transport pass cards, ID cards, etc., also embedded devices such as encryption modules.