| NAND Flash has become almost essential memory in the embedded device. The connection forms can be MCU integrated or external I/O. Pursuit of low-cost and high performance is persistent. Comparing the capacity and price, it's obvious that the greater capacity, the more cost-efficient. Nowadays, SD card and flash memory take G-bit as unit instead of M-bit. The use of high-capacity flash memory has become an inevitable trend. High-capacity flash memory is built by large page NAND Flash which is provided with highly storage speed. In the issue of how to use large page NAND Flash, original OEM can solve integrate program, however, for most plug-ins, we have to develop on our own. It is effortless for no-operation system but complicated for the ones with operation systems, because it involves Jtag burning, bootloader, OAL driver and application programs. To solve this is difficult, let alone bulk production. This paper is to address not only the technology, but also to achieve large-scale production requirements.This paper put forward two implement ways to operate large page NAND Flash: one is accessing at 2KB/page,the other one is dividing the large page into 4 pages. Though both have been realized, there are 3% machines of former cannot boot in practical use. In the absence of the source code, it can not be tracked by one-step FMD caller-driven to solved the problem fundamentally. It is ECC error according to the debugging information. The latter method is more reliable and more stable by comparison, with only 0.2% non-performing rate and more than 10 times enhancement in stability. The former is more desirable in academic aspect; however, based on the manufacturability, the later one is ultimately adopted. This paper is about Jtag downloading, bootloader implementation, FMD driver and relevant applications. The achievement is on embedded design notion, which determines the research profundity.(1)Embedded UML design: UML is generally considered to be applicable to large-scale information management system modeling, less in embedded design. Near upon 75% of embedded systems around the world are compiled by C. Because it often subjects to restrictions as well as the memory capacity of response speed to the high demands, only C and Assembly can meet the demand in general. With this huge industry trend and economic influence, the hale and hearty C language is still leading the embedded system development. Since UML is objected-oriented, it can be further used by C programmers. Due to the performance of UML in hardware integrated model, an increasing number of embedded systems are established by UML software and hardware integration model, known as software and hardware co-design (SW-HW Co-Design). According to the trend of combining SW and HW, embedded software quality is key to the digital home appliance products, the design and structure of software components (Architecture) technology programming industry is becoming the focus of attention. Put software and hardware designers work together to conceive whole frame. Software designers take full account of the variability of hardware to support hardware components with better design pattern (Pattern). Combine C and OO with UML Will be the platform for the success of digital products and embedded industry.(2)Embedded component-based system design: For years, embedded system engineers usually separate system into two basic components: operation system and embedded application. Later, other components are added, such as USB functions etc. Therefore, the concept of components have been in the mind of software programmers for a long time, not only today. People benefit from these components, besides reliability, time-to-market, easy-to-maintain, one of the most eye-catching advantages is flexibility. At present, however, most of embedded application is Monolithic Application. In the rapid 3C competitive environment, an increasing number of tricks demand in embedded software. Such as multi-media acousto-optic video, Broadband adoption of a long-distance transmission, all of these make software more complicate. To tackle this issue, we have to gather different opinions and demands, and then release more complicated version. Considering the opinions come from different area, the maintenance becomes difficult, then delay coming into the market. As an effective solution to these difficulties, it is necessary to change the traditional practice of the past. Based on the above-mentioned concept of the evolution of software, and the market environment factors, Component-based has become the ideal way to develop embedded software.(3)Recognition of components reliance: whether software and hardware components can be integrated harmoniously together is the key to success. First of all, this system should be paid attention to the overall structure to ensure the internal components' inter-change. Traditionally, programmers tend to analysis system flow and neglect system architecture design, which easily make one lose a detailed description of the unit, then overlook its own system as a whole, lead to a rigid system and lost. The improvement of structure provides a good foundation for the rapidly assembly of components and updated. As today's age of advanced communications network, the embedded software must maintain harmony in the rapid components elimination and restructuring process, and constantly innovate effectively adapt to the changing environment. It will be difficult to achieve overall harmony without stable and reliable structure. Architecture-Driven, also called Architecture-Centric, focuses on stability of the system architecture, as well as the flexibility in capacity expanding to ensure harmony, communication and co-operation among the system components. With the growth of enterprises, it is able to constantly update or add components. So that the components show the metabolic ability, and the system as a whole can grow healthy and strong.The success in large-page study made a revolutionary contribution to improving product performance, cost-effective, stability and maintainability, it has been effectively verified in the production of GPS products. Meanwhile, the process of realization promoted the understanding in embedded systems, FAT, SD card driver and UUID encryption. |
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