GPS is the abbreviation of Global PosiTIoning System (Global Positioning System) in English. In the field of machinery, GPS has another meaning: Geometrical Product Specific Specifications (abbreviated as GPS). Because GPS technology has all-weather, high-precision and automatic The characteristics of measurement, as advanced measurement methods and new productivity, have been integrated into various application fields of national economic construction, national defense construction, and social development. How to design a mobile device with GPS function to realize the reception and decoding of GPS satellite data is already a hot spot of CPS application. 1 Development platform 1.1 Software platform In order to adapt to the usage habits of most Windows users, we set the mobile device operating environment as the embedded operating system Windows CE 5.0, and the development process is carried out under the Windows XP operating system. The development software is Visual Studio 2005 and the programming language is C ++. VS2005 is a complete set of development tools under the Windows operating system, used to generate ASP Web applications, XML Web services, desktop applications and mobile applications. By using these tools and. NETFramework Lite can be created, generated, debugged and deployed in personal digital assistants (PDAs), mobile phones and other resource-constrained devices. Applications running on the NET Framework Lite. WindowsCE is the foundation of Microsoft's embedded and mobile computing platform. It is an open and upgradeable 32-bit embedded operating system. It is an electronic device operating system based on palm computers. It is a streamlined Windows 95, Windows CE The graphical user interface is pretty good. Windows CE is designed as a general-purpose operating system for small devices (it is a typical diskless system with limited memory). Windows CE can set the hardware platform by designing a layer of code between the kernel and the hardware, which is The well-known hardware abstraction layer (HAL) (in the previous interpretation, this is called the OEMC (original equipment manufacturing) adaptation layer, or OAL; the kernel compression layer, or KAL. To avoid confusion with Microsoft ’s Windows NT operating system, HAL). 1.2 Hardware platform 1.2.1 Embedded development board Since the operating environment used by the mobile device is set to WINCE 5.0, a large amount of data needs to be processed during the process, so the development board has higher requirements. Currently, the processors supported by WinCE 5.0 mainly include ARM, X86, PowerPC, and MIPS, among which ARM is a very influential microprocessor architecture in embedded systems in recent years. Taking into account the volume, power consumption, cost and other factors of the mobile terminal of this system, it is finally decided to choose the processor of the arm core. The development board is GEC2440 of the optical embedding company. 1.2.2 GPS receiving module The GPS receiving module is responsible for receiving GPS radio frequency signals, down-converting and demodulating the signals, and outputting standard serial port signals for the processor to process next. The GPS receiver module used in this design is the GPS-R36-AT module from Levave, and the performance parameters are shown in Table 2. The receiving module mainly includes a baseband chip and a radio frequency chip. It uses a SIRF III module, integrates a chip ceramic chip, does not require an additional antenna, receives C / A code satellite signals, and outputs signals as NMEA0183 protocol data. . 2 Overall design The design is mainly based on the flow of GPS data signals. The GPS data signal is read into the main program of the development board through the serial port, and then decodes the data signal to obtain the latitude and longitude information of the current position, and then queries the latitude and longitude database to obtain the name of the current position. Human-computer interaction. 2. 1 serial port driver Microsoft eMbedded Tools encapsulates Windows API functions to facilitate the development of Windows CE applications. In Windows CE, all devices are regarded as files. Serial communication can be achieved through API communication functions like accessing ordinary files. The virtual driver of the system is responsible for performing specific tasks. Under Windows CE, the serial port is regarded as a conventional installable streaming device for opening, closing, and reading and writing serial ports. It is a conventional I / O driver call of a serial device interface and a specific function related to communication Combine. The communication function of Windows CE is similar to the communication function of most other Windows. It is worth noting that Windows CE does not support programming the registers of the serial port directly. 2.1.1 Open and close the serial port The CreateFile function is used to open the serial port. m_hDSComm = CreateFile (_T ("COM2:")), GENER2IC_READ | GENER IC_WR ITE, 0, NULL, OPEN_EXISTIN-G, 0, NULL). Note that there is a colon after COM2. The third parameter dwShareMode must also be O, and the communication port cannot be shared like a file. The last parameter dwFlagsAnd-Attributes must be 0, because Windows CE only supports non-overlapping I / O. The return value of this function is the handle of the opened serial port or INVALLD_HANDLE_VALUE. Close the serial port can call CloseHandle (m_hDSComm). 2.1.2 Serial port parameter setting The serial port settings are mainly used to configure the port settings with DCB configuration, including baud rate, stop bit, data bit length, parity bit, flow control and timeout value, etc. First open the serial port, use the GetCommState function to get the currently open serial port configuration, then modify the DCB members as needed, and finally use the SetCommState function to set the new serial port configuration. 2.1.3 Set the buffer size and timeout For the serial port, you must set the timeout value, otherwise the program may fall into a loop to wait for characters from the serial port. For devices using WindowsCE, this will greatly reduce the battery life of the device, so the timeout value must be configured. Another solution is to use multithreading. Generally, the configuration timeout value is similar to the configuration serial port. First use the GetCommTI-meouts function to get the timeout value of the current serial port, then modify the COM2MTIMEOUTS member, and finally use the SetCommTimeouts function to set the timeout value. 2.1.4 Read and write serial port Use ReadFile and WriteFile functions to read and write serial ports. It should be noted that Windows CE does not support overlapping I / O, so if the main thread performs a large number of read and write serial port operations, it may cause the entire program to fall into a slow serial port wait, so generally multiple threads are used to read and write serial ports operating.
Control Cable includes general PVC Control Cable, Screened Control Cable and Armored Control Cable, they are suitable for fixed installations as connection and inter-connection cables in general machine,production lines.
Generally, Control Cables are Copper Wire conductor, PVC insulated or LSOH insulated and others, Tinned copper wire braid & Aluminium Foil, Copper Tape shielded, steel wire armored then PVC sheath or LSOH Sheath.
We supply lots of those Cable as per IEC 60227, BS 6500, AS/NZS 5000.1, VDE 0250, SABS and other requirements.
Control Cable,Control Wire,Cable Control,Kontrolfreek Cable Shenzhen Bendakang Cables Holding Co., Ltd , https://www.bdkcables.com
