首先研究CAN總線和SAE J1939協議,提出一種基于MC9S12HZ256微控制器的總線式汽車數字儀表解決方案。詳細介紹SAE J1939協議的報文幀格式及應用層協議中發動機相關參數的定義,以及步進電機及其驅動和車速信號的處理方法。該數字儀表系統硬件平臺由微處理器和信號采集和信息處理及顯示等模塊組成。軟件設計部分編程實現了對CAN總線和各傳感器數據的讀取、處理。該系統能夠實時反映車輛工況。
Abstract:
In this paper,CAN bus and SAE J1939protocol are researched,and a vehicle digital instrument solution based on MC9S12HZ256MCU is proposed.The message frame format and some engine-related parameters’definition in SAE J1939application layer protocol are introduced in detail.Stepper motor and its driver,the methods of speed signal process-ing are also introduced.The hardware platform of vehicle digital instrument is composed by MCU,signal acquisition mod-ule,and signal processing and displaying module.Data receiving and processing from CAN bus and sensors are accom-plished by programming,and vehicle condition can be reflected in real-time.
介紹了CAN總線和P87C591單片機的特點,給出了基于P87C591單片機的信號采集節點的軟、硬件設計,指出了硬件電路設計中應注意的問題,在軟件設計中重點介紹了節點初始化、報文發送和報文接收等子程序。
Abstract:
The features of CAN Bus and the microcontroller P87C591 are introduced, and the design of hardware circuit and soft configuration of the signals collection node based on P87C591 are presented. The problems in designing hardware circuit are discussed.Initialization subprogram, transmiting subprogram and receiving subprogram are emphasized in soft configuration.
針對船舶氣象儀保障維修而設計的船舶氣象儀測試系統,包括信息處理終端、主儀器檢測模塊、傳感器檢測模塊,各個模塊都采用基于AVR單片機的嵌入式系統,模塊之間通過CAN總線進行通信。結果表明,船舶氣象儀測試系統能夠快速檢測船舶氣象儀故障,與單純依靠人工方式排查故障相比,故障檢測時間縮短了60%以上。
Abstract:
The test system of ship meteorological instrument was developed to satisfy the maintenance of ship meteorological instruments,which composed of information processing terminal, testing module of main instrument and testing module of sensors. Each of these modules included an embedded system based on microcontroller of AVR series and communicated with other module by CAN bus. The results show that the test system can judge the fault of ship meteorological instrument quickly and shorten the fault detection time as much as 60% compared with simple manual troubleshooting.
SAE J1939協議是由汽車工程協會(SAE)定義的,SAE J1939協議在商用車輛、艦船、軌道機車、農業機械和大型發動機中是應用最廣泛的應用層協議,基于傳輸可靠性能優越的can-bus總線,可達到250Kbps的通訊速率。在協議中,不僅指定了傳輸類型、報文結構及其分段、流量檢查等,而且報文內容本身也做了精確的定義,SAE J1939協議由美國SAE( Society of Automotive Engineer)組織維護和推廣