Abstract: The blue tooth is one kind of short distance wireless communication technology, as a result of its low cost, the low power loss and the redundant reliable merit is widely accepted by the modern family network. In the article introduced the blue tooth technology and the family network basic concept which constitutes by each kind of information electrical appliances, as well as Motorola Corporation’s embedded processor MCF5272 some key property characteristic, and elaborated realizes the family blue tooth gateway’s concrete plan based on MCF5272. This kind of family blue tooth gateway mainly by the blue tooth gateway control module, the radio frequency receiving and dispatching module, outside the net interface module three parts of constitutions, also separately discussed each module principle of design in the article.
Key words: Information electrical appliances blue tooth family blue tooth gateway MCF5272
Introduction
The information electrical appliances (IA, Information Appliances) fused the computer and the communication new expense electronic products, along with the information electrical appliances further digitization, the network, intellectualized and the automated trend of development, presented the family network. But because blue tooth characteristics and so on technology low cost, low power loss, low complexity, high efficiency, redundant reliability, strong interoperability and good compatibility, cause it to accept by the family network. To manage in the network effectively reasonably the electrical appliances, and causes its to realize smoothly with the family network outside Internet, moves between the communications network even fixed city voice the correspondence, how does the blue tooth gateway realize, then becomes the question the key. This article based on the blue tooth technology, introduced realizes the family blue tooth gateway’s concrete plan with Motorola Corporation’s embedded processor MCF5272.
First, blue tooth and family network
The blue tooth (Bluetooth) is one kind of short distance wireless communication technology standard, uses for to describe and to stipulate that each kind of information product (including correspondence product, how computer product and expense electronic products) is uses the short distance radio system to carry on the connection. The blue tooth technology’s biggest advantage eliminated complicated, made the electric cable line which one had a headache, thus realized between the information electronic installation’s information transmission and the synchronization. It has the general electric cable in aspect and so on cost, security and bearing capacity all sorts of characteristics. Mainly has the following several characteristics:
l The blue tooth comes through the inserting chip for the existing equipment addition wireless connection function. This kind of micro chip’s area only then the 1cm square, can cause the equipment to transmit the radio signal in the short distance scope, seeks for another blue tooth equipment, once found, then started to correspond, the exchange information. The blue tooth may look like the Internet such transmission data, may also the image drift dynamic electricity voice such transmission pronunciation.
l The blue tooth’s wireless transmitting range is about generally 10m~100m, the emissive power probably is 1mv~100mv. What the blue tooth uses is the 2.4~2.4835GHz industry, the scientific research, the medical whole world passes the free frequency band. The major part country does not need in the world to apply for the radio license or the permit, enables the people to be possible the barrier not to use the blue tooth equipment anytime and anywhere. It uses the frequency-hopping to expand the spectrum technology, each second 1600 jump, when establishment connection is 3200 jumps, is the typical micropower equipment, is suitable for the family scope.
l The blue tooth equipment may realize the point-to-point correspondence, a blue tooth equipment are most may simultaneously and 7 equipment establishment wireless connection. The communication protocol uses the stratification structure, supports the pronunciation/data accessing spot, the peripheral device connection, individual network (PAN) and so on three big category applications. Uses the authentication, the encryption in the information link level, and the key management carries on the safety control. Uses PIN in the application layer (individual identification code) to carry on odd and even to the authentication.
l The blue tooth’s transmission speed may achieve each channel 1Mbit/s theoretically, time practical application’s effective value for each channel 721Kbit/s, probably is ordinary telephone line 13 times. It supports 64Kbps the real-time speech transmission, the speech coding uses PCM and CVSD. When only transmission pronunciation, supports three groups full-duplexes; When the pronunciation and the data simultaneously transmit or only transmits the data, supports the 433.9Kbps symmetrical duplex or the 723.2/57.6Kbps asymmetrical diplex operation.
Uses the blue tooth technology the family network to refer to the network electrical appliances and other equipment through inserts the blue tooth module, for instance the USB card, the UART card, the PCM card and so on, the use wireless way is causing its between to correspond mutually together continually, and using has the routing function family blue tooth gateway with the exterior network interconnection, can provide the centralism or the different place audio frequency/video communication, the computer control and the management and so on, realizes the information in the family as well as with the exterior between full correspondence and sharing.
Second, embedded processor MCF5272
The ColdFire microprocessor which the MCF5272 microprocessor is Motorola Corporation produces the Gaoji which becomes. Considers in the design next generation Internet equipment, the LAN telephone system, the low end network control, the industrial control, the image equipment, when saves the solution, Motorola’s MCF5272 high performance and the versatility can satisfy the embedded system design and the application request.
MCF5272 uses ColdFireV2 to be possible to lengthen the RISC processor nucleus and the DigitalDNA technology, can achieve 63MIPS under the 66MHz clock the fine handling ability. Its internal SIM (System Integrated Module) the unit integrated the rich general module, like 10/100Mbps fast ethernet controller, USB1.1 connection and so on, and can with the commonly used auxiliary equipment (for example SDRAM, the ISDN transceiver) realize the seamless connection, thus simplified the peripheral circuit design, reduced the product cost, the volume and the power loss. Mainly has the following characteristic:
l MCF5272 internal integrated 4K byte SRAM, 16K byte ROM, 1K byte instruction Cache, as well as outside the piece expands FLASH and SDRAM. Supports 8, 16 and 32 SRAM and the ROM, SDRAM controllers supports 16~256M the SDRAM chip. 32 bit address data bus, the essence and the main line clock is 66MHz, has 16 conventional data registers.
l MCF5272 internal integrated UART, the USB controller, only need the very few periphery chip be possible to realize two RS232 serial ports and USB the Slave connection. MCF5272 also in inlays FEC (fast ethernet controller), outside the piece expands piece of LXT971, the fast ethernet media access control (MAC), supports 100Mbps MII,10Mbps MII and 10Mbps the 7-Wire physical interface.
l The ColdFire series processor support background debugging pattern, it has provided to the first floor hardware’s debugging method. Under the background debugging pattern, through to the CPU routing directive, may realize visit to the CPU register, system memory’s. Uses the Motorola recommendation 26 needle plug to receive the BDM simulation head, realizes code downloading and the debugging.
l Conforms with the USB1.1 standard, in may operate or outside the transceiver equipment controller. Provides 48 general I/O pins, supports 7 external interrupt.
Third, the blue tooth gateway realizes the plan
The family blue tooth gateway realizes plan like chart Fig-1 to show, mainly includes the blue tooth gateway control module, the radio frequency receiving and dispatching module, outside the net linking module three parts. And, as the core part’s blue tooth gateway control module for has provided the wireless connection take MCF5272 to the family network through the radio frequency receiving and dispatching module with the information electrical appliances’ connection, with the PSTN net through the RJ11 connection connection, with the Internet net through the RJ45 connection connection, became the public net to enter the family outward the choke point.
1st, blue tooth gateway control module
The blue tooth gateway control module is the family blue tooth gateway’s hard core, has used Motorola embedded processor MCF5272, has good handling ability at the same time also to support blue tooth upper formation agreement functions and so on stack, terminal access control, telephone channel exchange. This design proposal has carried on the expansion to MCF5272 RAM and ROM, outside expanded 16M byte SDRAM (2×HY641620HG) and 4M byte FLASH ROM (2×AM29LV1600B). Thus, the MCF5272 execution saves, in dodges saves in FLASH the procedure, and stores some temporary data in synchro data stochastic accessor SDRAM, the user may and so on carries on the simple interaction through the keyboard and the liquid crystal display with MCF5272, completes some such as dates, the time and so on simple parameter establishment.
MCF5272 UART1 may direct and supports blue tooth connections and so on technology USB, RS232, PC card, realizes the upper formation and the first floor blue tooth agreement correspondence. Is directly connected through the serial port with the radio frequency receiving and dispatching module, and exterior the broken line may connect the telephone channel connection and the ethernet connection through the MCF5272 I/O pin. Except for this, the blue tooth gateway control module also includes the clock circuit, the reset circuit as well as the power source supplies several monitoring circuits and so on.
2nd, radio frequency receiving and dispatching module
The radio frequency receiving and dispatching module is composed of the blue tooth transceiver and the antenna, the function is provides the wireless channel for the gateway and the terminal. Each kind of control signal, the data signal carry on the transmission through the serial port and MCF5272. This module take the radio frequency unit controller chip as a core, by the filter, the power amplifier, low chirp puts, the receiving and dispatching cut switch and some peripheral circuit is composed. In order to cause the blue tooth’s transmitting range, in the spacious region can achieve about 100m, may consider before radio frequency controller adds the first-level radio frequency amplification electric circuit, implements the effective management by the controller chip’s built-in microprocessor to its memory unit and RAM, transfers the first floor blue tooth agreement stack. Namely through USB blue tooth equipment, RS232 blue tooth equipment, in PC card blue tooth equipment and family network information electrical appliances taper joint.
3rd, outside net interface module
Outside net interface module including telephone channel connection and ethernet connection.
The telephone channel connection uses from the transmission and the receiver transmission voice signal, the enlargement transmission DTMF signal. On the one hand comes from RJ11 the ringing and the double sound multi-frequency equisignal, delivers the DTMF receiver; On the other hand the enlargement from DTMF transmitter’s DTMF signal and from the PCM decoder’s voice signal, delivers on RJ11. The DTMF transceiver completes the DTMF signal the examination and the production, transmits supplies MCF5272 to the network to respond.
The ethernet connection and the telephone channel connection was together MCF5272 has provided the exterior channel, the network transformer played has isolated the RJ45 and circuit board the role, avoided disturbing mutually. The ethernet transceiver is playing the transparent transmission role, on the one hand turns mesh wire’s on difference serial signal MCF5272 to be possible to facilitate the read the parallel data, on the other hand turns the MCF5272 parallel data the difference signal to deliver on the mesh wire.
Concluding remark
Based on above blue tooth gateway control module, the radio frequency receiving and dispatching module, outside the net interface module, as the core family blue tooth gateway can realize take Motorola embedded processor MCF5272. Three module’s hardware costs are low, and the overall system design development cycle is short, the emissive power is low, the full use existing network resource has the upward compatibility and the extendibility, becomes winding which constitutes by the information electrical appliances key which with the PSTN net, the Internet net connects. This kind of family blue tooth gateway will certainly to become the blue tooth technology in the family network the application mainstream.
Reference:
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