Over the past two decades, as vehicle complexity has increased, engineers have upgraded ECUs from 8-bit MCUs to more than 16-bit devices. Currently, such a highly integrated 32-bit RISC MCU is the Renesas SH7058, an 80MHz MCU with 1MB of on-chip flash and 48KB of RAM. Due to a variety of system requirements, such as controlling extended-level input/output (I/O), communication with other in-vehicle systems via secure communication links (such as CAN and Flexray), and processing algorithms with floating-point precision, The use of high-speed 32-bit MCUs in today's ECUs is an essential configuration.
This article refers to the address: http://
In addition to bringing new performance advantages, the latest 32-bit MCUs reduce board design complexity, save overall PCB space, reduce system power requirements, and reduce electrical noise and immunity to electromagnetic interference (EMI). Ability. Typically, the cost of manufacturing each ECU ranges from about $70 to $100. At this cost, an MCU accounts for 15%-20% of the total cost.
Systems with 32-bit MCUs are often very complex and typically take two to four years to complete an ECU project. The design team typically consists of 1-2 hardware engineers and 4-5 software engineers. In order to achieve the desired progress, all milestones and required resources must be properly identified. In addition, the design process from concept definition to production must be consistent with the beginning.
The project plan should identify the design environment, especially the development tools, and consider the test and commissioning plan. Figure 1 illustrates in schematic form a hypothetical ECU system diagram.
System partition
In the early stages of project development, the main goal is to determine what functions are implemented in hardware and what functions are implemented in the software. This decision will be influenced by factors such as project budget, component cost, PCB space, and mission deadlines, so trade-off decisions need to be made. In ECU design, a large number of algorithm modeling and system simulation are needed to solve the optimization problem of design partitioning. Currently, there are some vendors that offer solutions to the problem of design partitioning.
Software problem
When developing 32-bit systems, software engineers must consider ways to solve many problems. In ECU applications, if the verified code from the previous design can be reused, it will save time and the workload will be reduced. Most embedded designs use C, so the code can be reused at a high rate.
However, migrating the original code requires changing the peripheral driver and code section, which shows the project with a specific relationship to the MCU design. We recommend using a device driver code generation tool like IAR's MakeApp that saves hours of design time.
Other important issues related to code development work projects cannot be ignored:
* Real-time operating system selection: There have been many papers and articles that give advice on how to choose a real-time operating system. For ECU design, OSEK has evolved into an industry-standard RTOS that is deterministic, robust, efficient and stable from many suppliers.
* Debug mode: Software engineers should be confident that they have sufficient ability to troubleshoot and troubleshoot when the project enters the integration phase. Although the code simulator is fairly reliable, integration problems still exist. What should I do at this time? The answers vary. Taking the ECU design as an example, a full-speed traditional in-circuit emulator (ICE) is expensive ($12,000). It is not only difficult to apply online simulation in the engine compartment, but also cannot be used to solve difficult timing problems.
In contrast, the on-chip debug (JTAG) emulator is economical ($1,000) and easier to connect to the system. For example, Renesas' E10A is a JTAG-compatible hardware debugger that allows engineers to interrogate and control the register set and the RAM memory of a super-high processor. In addition, to improve the accuracy of the ECU code, software engineers must be able to take advantage of some of the characteristics of AUD (Advanced User Debugging), which forms a special trace of the ultra-high speed CPU pipeline. In the Renesas SH7058 MCU series, the AUD interface on the MCU is bidirectional, and the RAM can be stored without suspending the CPU.
hardware problem
A lot of hardware problems will be encountered during the development of 32-bit systems. The following points deserve special attention:
* Power supply filtering: Most 32-bit MCUs run much faster than 16-bit MCUs. In addition, 32-bit MCU CPU cores require independent low-voltage power supply systems, so their noise margin is stricter than I/O circuits. many. Therefore, sufficient low-frequency and high-frequency decoupling capacitors should be placed around the PUB, especially in the vicinity of the MCU. Practice has shown that decoupling capacitors can effectively reduce noise.
* On-chip flash: In the past, many MCUs used in ECU systems did not have enough memory to run as a single-chip controller, and some MCUs had no program memory at all. As a result, program memory was placed outside the chip due to A large number of high-speed addressing and data buses are required, which often leads to EMI problems.
Currently, 32-bit ECUs like the SH7058 have 1 MB of flash memory, a true single-chip solution feature. In most cases, off-chip memory is no longer needed due to the large amount of on-chip program memory. In the ECU design using the SH7058, the on-chip flash memory can be cured in two ways, one is to cure the device before the motherboard is manufactured, and the other is to solidify in the system after the motherboard is designed, so that the software engineer There is a lot of flexibility in upgrading the code, and engineers can even upgrade with the car bus (CAN) after the ECU is installed inside the vehicle.
Summary of this article
The leap from 16-bit to 32-bit MCU is a qualitative leap, and this trend is inevitable. The 32-bit implementation greatly enhances the computing power and operational performance of the system. The key to successful conversion is adequate preparation, training, and careful development tool selection strategy. In addition, the 32-bit MCU vendor like Renesas continues. Support is also crucial.
10-inch tablet devices have greatly surpassed netbooks in terms of entertainment, including reading, games, and audio-visual enjoyment. In other respects, the basic operation of the 10-inch tablet computer built on the touch screen ensures that the application of the tablet computer can be well realized, and its operation performance is closer to that of a smartphone.
1.In appearance, the 10-inches tablet computer looks like a large-screen mobile phone, or more like a separate LCD screen.
2.In terms of hardware configuration, the 10-inches tablet computer has all the hardware devices of a traditional computer, and has its own unique operating system, compatible with a variety of applications, and has a complete set of computer functions.
3.The 10-inches tablet computer is a miniaturized computer. Compared with traditional desktop computers, tablet computers are mobile and flexible. Compared with Laptops, tablets are smaller and more portable
4.The 10-inches tablet is a digital notebook with digital ink function. In daily use, you can use the tablet computer like an ordinary notebook, take notes anytime and anywhere, and leave your own notes in electronic texts and documents.
10 Inches Tablet Pc,Tablet Pc Android,10 Inch Quad Core Tablet,Tablet 10 Inch
Jingjiang Gisen Technology Co.,Ltd , https://www.jsgisengroup.com