Optimization and Data Analysis of LCD NCM Transmission System for Automotive
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摘要: 为探索NCM技术实际应用的可行性,解决当前汽车液晶仪表传输带宽不足及车载以太网应用成本过高的问题,本文对NCM工作环境进行了分析。通过设计NCM USB兼容接口和网络解码器,优化NCM系统传输过程,设计了NCM传输系统。数据处理发现,该系统单一条件下最优工作帧为20帧,极限传输速率达到22.5 M/s,可用于汽车的高带宽数据传输。为确定NCM传输的最优工作区间,分析多因素对NCM传输的综合影响,引入了数学模型对系统进行评估。结果表明,NCM技术可用于特定条件下汽车的高带宽数据传输。当分辨率为600×240、工作帧18帧时,流畅度为0.85,视频流的传输效果最好。该研究在提供低成本高带宽的NCM传输方案的同时,提供了NCM传输工作环境的数学评价模型,为NCM技术的应用提供了理论支持。Abstract: To explore the feasibility of practical application of NCM technology, solve the insufficient transmission bandwidth of LCD(liquid crystal instrument)and high cost of Ethernet in vehicle, the working environment of NCM is analyzed. Through the design of NCM USB compatible interface and network decoder, the NCM transmission process is optimized, and the on-board NCM transmission system is designed. Data processing found that the optimal working frame of this system is 20 frames under a single condition, and the limit transmission rate reaches 22.5 M/s, which can be used for high-bandwidth data transmission of automobiles. To determine the optimal working interval of NCM transmission, the comprehensive influence of the multiple factors on the NCM transmission is analyzed, and the model to evaluate the system is introduced. The results show that NCM technology can be used for high bandwidth data transmission of vehicle in certain conditions. When the resolution is 600×240 and the working frame is 18, the fluency is 0.85, and the transmission effect of the video stream is the best. The present study not only provides the NCM transmission scheme with low cost and high bandwidth, but also provides the evaluation model for NCM transmission working environment, which provides theoretical fundamental for applying the NCM technology.
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Key words:
- instrument /
- data transmission systems /
- optimization /
- models /
- data processing
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表 1 NCM接口控制描述符定义表
USB描述符 Value 描述符 接口编号 0XNN 指定接口编号 接口类 0XFF 特定Device接口 0X0A USB数据接口 接口子类 0X0D 网络控制模型 接口协议 0X00 没有封装命令/响应 0X01 NCM协议栈 接口字符串 I.MX6 Device特定硬件接口 端点数量 1 Interrupt IN端点 2 bulk IN端点和bulk OUT端点 表 2 序号对应分辨率定义表
序号 分辨率 序号 分辨率 1 128×96 6 720×480 2 176×144 7 800×480 3 320×240 8 800×600 4 400×240 9 1280×720 5 600×240 10 1 920×1 080 -
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