FlexRay Solutions by NEC Electronics

Take control.

Network standards like CAN tend to act as a limiting factor when it comes to reliability, availability and bandwidth. To break this impasse, the FlexRay protocol has been specified as a route to a new network standard that offers high bandwidth, fault-tolerant operation and deterministic behaviour as a basis for advanced future automotive applications, such as steer-by-wire and brake-by-wire. The FlexRay baud rates of up to 10 Mbps open up new dimensions of automotive communication. Two redundant communication channels support fault-tolerant operation. Unlike event-triggered systems such as CAN, FlexRay is based on a time-triggered architecture where communication is organized in predefined time slots on the FlexRay bus. This ensures deterministic behaviour with predefined latencies and avoids bus overloads.

NEC Electronics has accumulated substantial experience in time-triggered communication protocols. Before the CAN protocol was becoming widely accepted, NEC was already generating the ideas necessary to establish a global time system in a distributed network, granting free access to its patent on global time synchronization later on for the ISO standardization of TTCAN. As an associate member of the FlexRay consortium since February 2003, NEC Electronics is now turning FlexRay theory into reality with first silicon implementations. These support FlexRay with the following feature set:

Protocol V2.1 or higher
Two communication channels
Data rates up to 10 Mbps on each channel
Configurable message buffer sizes, e.g.:

128 message buffers with max. 48 byte data field down to
30 message buffers with max. 254 byte data field

Configuration of message buffer with different payload lengths possible
One configurable receive FIFO
Filtering for frame ID, channel ID, and cycle counter
Network management support
Host access to message buffers via I/O buffer
Shadow I/O buffer for optimized CPU access
2 x maskable interrupt for error and status information
2 x timer interrupt

click to enlarge the FlexRay blockdiagram...

Central to the FlexRay module is the message handler (MHD) that controls the handling of messages and functions such as acceptance filtering, transfer of messages between FlexRay channels and maintenance of the transmission schedule. The CPU accesses and controls the MHD and other units of the FlexRay controller, like the global time unit or interrupt control, via dedicated registers.

Safety

As electronics reaches inexorably into virtually every aspect of cars and driving, safety has become one of the key issues for new developments. FlexRay was designed to overcome the limitations of the old CAN networks in this area. A safety concept, however, need not stop at the interface. NEC Electronics provides additional features like self-test capability, supported by specific test modes for RAM test, loop-back test or drive-out pin test, or RAM content protection by parity check and ECC. These features help to make its FlexRay devices a valuable part of the overall safety concept.

FlexRay Microcontroller "Family"

NEC Electronics have extended their successful 32-bit V850 MCU family with devices that feature an embedded FlexRay communication controller (FRCC) in different performance and memory ranges for all kinds of applications.

Chassis MCU: V850E/PHO3

The V850E/PHO3 is NEC’s first MCU with embedded FlexRay. This powerful 32-bit RISC microcontroller is optimized for inverter control applications requiring control of up to two 3-phase brushless DC motors simultaneously, for example in electronic power steering, braking or damping. Equipped with an embedded FRCC that is based on the Bosch E-Ray IP-Module R1.0 and 2 CAN interfaces, the V850E/PHO3 is designed for advanced network architectures and future x-by-wire applications. Its on-chip safety features, e.g. CRC, ECC on flash and RAM, meet the highest safety requirements and supports application targeting IEC61508 SIL3 certification.

Figure: V850E/PHO3Package

The ES1.0 version, used to build the first FlexRay ECUs for evaluation purposes, has been available since the end of 2005. Recently the Phoenix-FS ES2.0 version was released. Featuring the latest FlexRay IP-Module, E-Ray R1.0 (FlexRay spec v2.1), this microcontroller goes into mass production in 2008, and will then be found in several chassis domains like electronic power steering, damping and vehicle dynamics control applications.

Features:

V850E @ 128 MHz with FPU
1MB Flash / 60KB RAM
FlexRay (2 ch, v2.1)
2 x CAN (32 + 32 msg. buffer)
2 x CSI, 2 x buffered CSI, 3 x UART,
2 x ADC (10+10 ch), 10 bit, 2 us
2 x real-time pulse unit for motor control
357 PBGA

Body & Gateway MCU: V850E/CAG4-M

As a leading semiconductor manufacturer for automotive gateway microcontroller, NEC Electronics will naturally be enlarging the gateway MCU family with the addition of an embedded FlexRay device. Called V850E/CAG4-M, this device will feature up to 6 x LIN-UART, 6 x CAN, FlexRay, and an integrated MediaLBTM interface for MOST®.
Apart from gateway applications, the V850E/CAG4-M is also intended for other high-performance applications in the field of body electronics and also vehicle chassis.

Features:

V850E @ 80 MHz with FPU
512KB Flash / 60KB RAM
FlexRay (2 ch, v2.1)
3-wire MediaLB interface
6 x CAN (6x48 msg. buffer; mirror mode)
4 x CSI, 6 x LIN-UART (+MLM), I2C
ADC: 10 ch, 10 bit, 2 us
144 QFP

Further microcontrollers from NEC Electronics with embedded FlexRay are already on the roadmap which will cover future automotive application in the electronic segments: chassis, safety, body, gateway and audio.

Figure: NEC FlexRay MCU roadmap

All NEC FlexRay microcontrollers offer fastest access to the FRCC via a 32-bit non-multiplex synchronous interface, which reduces CPU load to a minimum!

FlexRay controller testing activities

NEC Electronics conducts extensive in-house evaluation of the FRCC on simulation and application level. In addition to NEC in-house testing activities, all NEC microcontrollers undergo the FlexRay conformance test (CT), a fundamentally important test showing correct functionality with regard to the FlexRay CT specification. As a worldwide first microcontroller with embedded FlexRay, the NEC V850E/PHO3 passed the FlexRay CT at TUEV NORD in March 2007 (see picture of certificate).

Figure: V850E/PHO3 FlexRay Conformance Test Certificate

Furthermore NEC is an active member of the JasPar consortium, which conducts several stress and interoperability tests capable of proving that the NEC V850 MCU also runs correctly in an inhomogeneous FlexRay network.

AUTOSAR and tool environment

NEC Electronics joined the AUTOSAR partnership as a premium member in March 2004. As NEC Electronics' main area of expertise is microcontrollers, the focus of its activities within the AUTOSAR partnership is on software modules that are either very close to, or directly interact with microcontroller hardware.

Already NEC is systematically bringing the AUTOSAR standard and methodology to bear on the product development process. The goal is clear: to enable NEC Electronics to provide system solutions (hardware and software) that not only support, but also enhance the implementation of AUTOSAR-compatible software.

Figure: AUTOSAR Software Architecture

To facilitate the introduction of AUTOSAR on the market, NEC developed an AUTOSAR Starter Kit which includes both hardware and software. The hardware consists of an evaluation board on which the V850E/PHO3 MCU and many interfaces are mounted. The software contains the complete AUTOSAR Micro Controller Abstraction Layer (MCAL) including the FlexRay Driver/Interface SW, and a configuration tool.
The AUTOSAR Starter Kit will be ideal for software engineers who would like to start working with AUTOSAR, and is the perfect way to create first FlexRay applications. It will include the following features:

Hardware: