In-vehicle network architectures have become more complex over the past decade. Although the number of in-vehicle network protocols has decreased, the number of actually deployed networks has increased significantly. This raises the scalability issues of network architectures and requires optimization of semiconductor devices to meet the practical needs of various applications and networks.
FPGAs were once considered a development-only solution, but today their price drops are so rapid that many problems are solved and can even be put into production at a lower overall system cost than traditional ASIC or ASSP solutions. Now, all major FPGA vendors for the automotive market have passed ISO-TS16949 certification, making programmable logic devices gradually become the mainstream technology in the automotive market.
Vehicle network electrical architecture
Over the past decade, network protocols for many specialized car manufacturers have given way to more standardized global agreements such as CAN, MOST and FlexRay. As a result, semiconductor suppliers can focus on manufacturing devices that comply with these protocols, and make first-tier component suppliers more competitive and price cuts, while also facilitating module interoperability between automotive OEMs. However, there are still many problems in today's automotive electrical architecture that plague automotive OEMs and Tier 1 accessories suppliers.
Engineers can divide and develop network policies in several different ways. High-end cars can run up to seven different network buses simultaneously. For example, a car can have a LIN loop for rearview mirrors, a 500Kbps low-speed CAN loop for low-end functions such as seat or door control, a 1Mbps high-speed CAN loop for body control, and another high-speed CAN loop. For driver information systems, a 10 Mbps FlexRay loop to provide real-time driver assistance data, and a 25 Mbps MOST loop for transmitting control and media streams within or between multiple infotainment systems, such as navigation or rear seat entertainment .
On the other hand, a low-end car can have only one LIN or CAN loop, allowing all other modules to work independently with virtually no interaction. Different OEM car manufacturers handle inter-module communication and automotive network topologies in different ways, and each vehicle platform is different, making it difficult for Tier 1 suppliers to develop a modular architecture that has both the correct interface and reusability. The uncertainty of the final architecture of the housing module is where FPGAs come into play.
ASICs, ASSPs, and microcontrollers have a fixed hardware architecture, and their resources are often not lacking or surplus, and there is no flexibility. The programmability (and reprogrammability) of FPGAs facilitates the addition and subtraction of on-chip channels (such as CAN channels) and allows for the reuse of IP. With this flexibility, the number and type of network interfaces can be optimized. The solution was quickly made into modules.
Semiconductor implementation of network protocol
The strength of FPGAs is not only the scalability of the number and type of interfaces. For ASSPs, ASICs, and microcontrollers, their peripheral macros are implemented in hardware, so they lack flexibility. In the FPGA environment, the network interface IP itself can be optimized according to the IP used.
For example, with Xilinx LogiCORE CAN or FlexRay network IP, users have the flexibility to set the number of transmit and receive buffers and the number of filters. In traditional hardware solutions, engineers using CAN controllers typically have only three configuration choices of 16, 32, and 64 message buffers. Depending on the level of system functionality and the processing power available outside the FPGA, Xilinx's scalable MOST network interface solution includes network controller IP that can be configured for primary or slave operation as well as asynchronous sample rate converter (ASRC), data router or replication. Protect a large number of IPs such as encryption engines.
This IP allows for optimization that can be incorporated into lower-density devices in low-end solutions as well as higher-density devices in high-end solutions, and often uses the same package outline on the target board of the module. In addition, for each major protocol, the industry has developed a middleware stack and driver for a complete solution. This scalability and versatility of FPGA solutions is simply not possible in traditional automotive hardware solutions.
All major FPGA vendors have soft microprocessors that can be efficiently implemented in the architecture of control functions and run at speeds comparable to those embedded in some hardware. Another big advantage of the FPGA architecture is the ability to offload processing tasks on microprocessors and partitions by using parallel DSP processing in a multiplier or on-chip hard MAC to improve overall performance and throughput.
Programmable logic devices have made great progress
Programmable logic devices have made great strides and are gradually becoming the mainstream technology in the automotive market. Various programmable logic devices are indistinguishable in terms of reliability, while FPGA technology enables scalable and flexible integration, which is not possible in traditional ASIC, ASSP or microcontroller architectures. The shortened development cycle, the use of advanced process technology by programmable logic device vendors, and the economies of scale that programmable devices inevitably bring, all contribute to lower overall production system costs.
As key IP and solutions for in-vehicle networks mature and the performance potential of FPGA architectures increases, programmable logic devices will play an important role in overcoming some of the engineering challenges inherent in automotive electrical architecture development.
Guangzhou Yunge Tianhong Electronic Technology Co., Ltd , http://www.e-cigaretteyfactory.com