With the rise of China's automobile industry, the demand for related automotive electronic products is growing, and it has become a hot spot for research and development in the automotive industry and the electronics industry. Under the theme of “entertainment, comfort and securityâ€, in-vehicle information multimedia products are evolving into a large platform that integrates multiple emerging technologies.
This article refers to the address: http://
The wireless car multimedia terminal introduced in this paper integrates communication, entertainment and security control. It adopts 32-bit MIPS microprocessor Au1200, which has the characteristics of system integration, function diversification, technology integration and communication network, which satisfies the requirements. The requirements for the development of in-vehicle information multimedia technology can be widely applied to transportation systems such as railways, subways, and passenger cars.
2 System Overview
The system adopts a client/server architecture, which consists of a wireless vehicle multimedia terminal, a station server, a monitoring center, and a communication network. The system architecture is shown in Figure 1.
The main functions of the wireless car multimedia terminal are as follows:
When the wireless data transmission vehicle returns to the terminal station, the vehicle terminal establishes a communication link with the station wireless AP through the 802.11a/b/g wireless network card, automatically transmits the playback result file to the server, and downloads the playlist and the multimedia file to the local hard disk.
When the remote monitoring and management vehicle is driving on the line, the GPS technology is used to transmit the position and speed of the vehicle to the monitoring center by means of short message or GPRS data communication. The control command of the monitoring center is also sent to the vehicle terminal through the GPRS network for real-time operation. Information exchange.
Multimedia file playback can be operated according to user input, such as play, stop, pause, play progress adjustment, volume adjustment, and so on.
3 hardware design
The terminal selects AMD's Alchemy Aul200 as the main control chip. This is an embedded CPU based on MIPS architecture with powerful audio and video processing capabilities. Its rich peripheral interface and low power consumption provide an ideal design for in-vehicle electronic products. The terminal hardware framework is shown in Figure 2.
The terminal mainly includes a storage module, a multimedia processing module, a wireless communication module, and a USB interface module. The circuit design of several modules is described below.
3.1 storage module
The system memory module is composed of dynamic memory, static memory and local memory, and its design is based on the memory interface characteristics of the Aul200 chip.
3.1.1 Dynamic Memory Design
The Aul200 has a DDR SDRAM memory controller on-chip. In order to meet the application requirements, the system uses two NT5TU32M16AGs to construct a 32 b dynamic memory system in parallel. Each NT5TU32M16AG has a storage capacity of 8 Mb×16 I/O×4 banks and a data width of 16 b, which is mainly used as the running space of the system program. The interface circuit is shown in Figure 3. The two chips share the chip select signal, the read/write signal and the address line, and the data output is combined into a 32 b data bus.
3.1.2 Static Memory Design
This design uses a piece of TE28F128J3C NOR FLASH as a static memory. The chip has a data width of 16 b and a storage capacity of 16 MB. It is mainly used to store bootloaders, operating systems, file systems, and applications. The FLASH is mapped to the base address 0xBFC00000 of the Aul200 storage space by connecting the CE0# of the FLASH and the RCS0# of the Aul200. When the system is powered up or reset, it will be started from this address.
3.1.3 Local Memory Design
To meet the storage needs of video files, this terminal is equipped with a 20 GB IDE hard disk. The logic control of the hard disk interface is realized by CPLD. The HD_CS[n] of Aul200 and the A6~A4 pins form an address bus for accessing the internal registers of the hard disk; the 16-bit data buses D0~D15 are level-converted by the bus transceiver 74LVC245. Connected to the hard drive.
3.2 multimedia processing module
Aul200 has powerful multimedia processing functions, and can support MPEG2, MPEG4, AVI, MP3 and other media formats. Its on-chip media acceleration engine MAE and programmable controller PSC provide great convenience for audio and video processing.
3.2.1 Video unit
The system uses a television as a display terminal. By converting the progressive scan signal output from the Aul200 LCD interface to an interlaced signal, the display input requirements of the television can be met. The selected video scan conversion chip is Focus EnhanceMent's FS453. The interface circuit between Aul200 and FS453 is shown in Figure 4.
In order to ensure the quality of the converted image, the FS453 needs to work in the pixel clock mode of the virtual host. The CLKOUT pin output of the FS453 is used as the input clock of the Aul200 LCD controller. The FS453 controls the rate at which the Aul200 transmits digital video signals. The Aul200 provides the horizontal synchronization signal LCLK, vertical sync signal FCLK, pixel clock signal PCLK and bias signal to the FS453. BIAS to achieve coordination between the two.
The FS453 first converts the received image data into YcrCb format, and scales the number of image lines and the number of pixels per line according to the SDTV standard, then removes the flash and encodes it into a broadcast-quality interlaced SDTV video, and finally passes The four DAC channels are sent to the S terminal.
3.2.2 Audio unit
The terminal uses audio codec chip UDA1380 and CPU programmable serial controller (PSC) to form an audio processing circuit, which has interfaces such as line input, microphone input and stereo output. The circuit diagram is shown in Figure 5.
The PSC supports four working protocols: AC97, IIS, I2C, and SPI. The system sets PSC0 to IIS mode by setting register psc_sel, and PSC1 is I2C mode. Among them, PSC1 is used to control and initialize UDA1380, and PSC0 is used to transmit audio data. During playback, the Aul200 sends data to the DATAI pin of the UDA1380; during recording, the Au1200 receives data from the DATAO pin of the UDA1380.
3.3 Wireless Communication Module
While implementing audio and video processing, the terminal also integrates wireless technologies such as GPS, GPRS, 802.11a/b/g to realize remote monitoring management and wireless data transmission.
GPS selects JP7-T of FALCOM Company. The power consumption of this module is only 200 mW during normal operation, which meets the requirements of low-power consumption of vehicle terminals, mainly by RF down converter, digital baseband demodulator, embedded ARM processor and The internal GPS processing software consists of four parts. The Au1200 sends a setup command to the JP7-T module to control the status and working mode of the GPS. Thereafter, it receives its own location, speed, and other information, and stores it in the external FLASH for GPRS transmission.
The GPRS module uses Sim300, which is produced by Simcom. The module supports GSM/GPRS 900/1 800/1 900 MHz tri-band network and embeds a powerful TCP/IP protocol stack. After the module power-on reset, first set the working parameters, and then obtain the local dynamic IP by configuring the network to complete the GPRS Internet access.
The wireless network card uses ASUS WL-167G. The network card supports 802.11a/b/g protocol. The outdoor coverage distance is up to 330 m and the maximum transmission rate is 54 Mb/s, which can meet the requirements of station AP coverage and data transmission rate. It solves the problems of large workload and poor timeliness caused by manual loading of data.
In the above module, the GPS and GPRS modules are respectively connected to the UART0 and UART1 of the Au1200, and the WL-167G is connected to the extended USB port.
3.4 USB interface module
The Au1200 includes a USB controller that supports EHCI and OHCI. This design uses USB Hub chip GL850A to expand 4 sets of downlink ports, compatible with high speed / full speed / low speed device transmission. The extended USB port is used for external cameras, wireless network cards, wireless network cards and other devices.
4 Conclusion
This paper introduces a hardware design scheme of wireless vehicle multimedia terminal based on Au1200. Its advantages are: low cost, low power consumption, rich interface, strong scalability, and meet the information management and intelligent management requirements. With the continuous regulation of the in-vehicle information multimedia system industry and the further advancement of information infrastructure construction, the terminal will have a broader market prospect.
Smart mini garden spotlight, 9 pcs for 1 kit, two power versions are available, with a driver, adaptor and 10 meters cable. The mini garden spotlight has both lighting and RGB colorful lighting mode, the angel of lamp head can be changed. Lamp body is waterproof IP66, rainproof and dustproof. It can be easily inserted on lawns, gardens and beaches.
The light is power supply, and the 10-meter cable is enough to connect with electric power. Whether it's a cloudy day or a rainy day, you can always light up your garden.
The light color, brightness, cycle mode and timing can be controlled by App.The App are developed on the most advanced Bluetooth Mesh technology. [LinkupHome" App can be downloaded in the App store or Google Player, then you can control our product without any complicated steps. The App is stable, easy control and multifunctional.
The advantages of Bluetooth Mesh are fast connected, low power consumption, no password required and Ad-Hoc Network. No need WIFI and hubs, as long as you have a Bluetooth-enabled smart phone, you can experience the smart light. When you install several smart gardenspots, the self-organizing network function can make the signals free connected, break the limitation of distance.
Plug-in Electric Outdoor Light
Solar Garden Lights,Outdoor Strip Lights For Garden,Garden Outdoor Strip Lights,Plug In Electric Outdoor Light
Ningbo Homey Photoelectric Tech. Co., Ltd , http://www.linkuphome.com