Renesas releases free-of-charge self-test MCU Software for safety compliance

September 14, 2011 // By Christoph Hammerschmidt
Renesas Electronics Europe has received VDE (the German Association for Electrical, Electronic & Information Technologies) certification for its IEC60335-compliant self-test software for the RX600 and RL78 microcontroller (MCU) families. These self-test CPU software routines developed for the RX600 and RL78 families are compliant with IEC60730-1 regulations and have now been certified by VDE.

Developers of Firmware for safety-critical applications and appliances benefit from the new certification because the VDE approved software is suitable for all of Renesas' RX600 and RL78 MCUs, a Renesas spokesperson said. VDE is widely recognized for its efforts on safety standards and approvals.

In addition to the on-chip hardware safety features, the self-test CPU software makes it easier for manufacturers of industrial, motor control and home appliances to meet IEC60730-1 (IEC60335) class B safety requirements. The IEC 60730-1/60335-1 safety standards require software running on an MCU to be able to detect any safety-critical failures according to specific fault models.

The RL78 and RX600 MCU families integrate on-chip key advanced peripherals like the CRC (cyclic redundancy check engine), the analogue-to-digital (A/D) converter which integrates a self-diagnosis function to ensure the plausibility checks, and a hardware clock monitoring function. Finally, the RL78 MCU integrates a RAM parity error check to secure the storage of safety relevant variables.

Renesas has been successfully certified for its periodic test routines for CPU registers and program counter test, stack test, RAM tests (using March X and C algorithms), Flash check (using cyclic redundancy check engines) and clock monitoring tests.

The routines are said to be easy to integrate in any existing software and can be called after reset and periodically during run-time. This software enables developer to design safety relevant software and to meet the certification process quickly and with less effort. It can reduce development time and the test harness process by up to 3 months, and the cost of certification by 15 percent.

The software source codes in C and ASM for the RX600 and RL78 families of MCUs are available on the Renesas website with detailed timing of routines, application notes and the VDE certificate: