The FlexRay protocol has been specified as a route to a 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 10Mbits/s makes it suitable for automotive communication applications. Two redundant communication channels support fault-tolerant operation. FlexRay is based on a time-triggered architecture where communication is organised in predefined time slots on the FlexRay bus. This ensures deterministic behaviour with predefined latencies and avoids bus overloads.NEC Electronics' silicon implementations of FlexRay theory support FlexRay with a set of features including: protocol V2.1 or higher; two communication channels; data rates up to 10Mbits/s on each channel; configurable message buffer sizes; 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 through I/O buffer; shadow I/O buffer for optimised CPU access; 2 x maskable interrupt for error and status information; and 2 x timer interrupt.
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, through dedicated registers.
NEC has extended its 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. The V850E/PHO3 is an MCU with embedded FlexRay. This 32-bit RISC microcontroller is optimised 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 high safety requirements and supports application targeting IEC61508 SIL3 certification.
The ES1.0 version, which was used to build the first FlexRay ECUs for evaluation purposes, is available from NEC. Recently the Phoenix-FS ES2.0 version was released. Featuring the new FlexRay IP-Module, E-Ray R1.0 (FlexRay spec v2.1), this microcontroller is suitable in electronic power steering, damping and vehicle dynamics control applications. Features of this microcontroller include: V850E at 128MHz with FPU; 1Mbyte Flash / 60Kbyte 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, 2us; 2 x real-time pulse unit for motor control; 357 PBGA
NEC also expanded its 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. The features include: V850E at 80MHz with FPU; 512Kbytes Flash / 60Kbytes RAM; FlexRay (2ch, v2.1); 3-wire MediaLB interface; 6 x CAN (6x48 msg. buffer; mirror mode); 4 x CSI, 6 x LIN-UART (+MLM), I2C; ADC - 10ch, 10 bit, 2us.
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 can be useful for software engineers who would like to start working with Autosar, and is an optimal way to create first FlexRay applications. The hardware features include: PCB with V850E/PHO3; interfaces for FlexRay, CAN, CSI, UART; interface for an external FPGA; motor control interface; display and LEDs for signalling test results. The software features include: Autosar MCAL software; Autosar configuration tool; demo application; and documentation.
