The Power Management Design And Implementation Based On MOST Networks

With the deepening of the car informatization, the number of automobile electronicequipment is growing and the corresponding MCU are becoming more and more. Now a caroften includes dozens of MCUs, so the increase of the MCUs and incidental communicationequipments will make the complex circuit and wire, a big weight, a high cost. In order toreduce the communication equipments and plugins, cost and simplify lines, the high-speedmulti-channel communication system was used to transmit control message by sharing. So thenetwork was put forward, at present the universal network ware CAN and LIN. For theinformation entertainment system such as DVD video system, electronic map system andremote information access system, CAN and LIN network, regardless of on the networkbandwidth, anti-interference or quality can't meet the application requirements. In order tosolve the problem of information entertainment equipment, MOST cooperation organizationdeveloped MOST standard. The network was high speed, low cost, anti-jamming, light quality,flexible, so it was increasingly used in the TV, car phone, car CD, audio and navigationsystems.With the audio-visual equipments, communication equipments and the informationservice equipments increased, MOST improved comfort and convenience of cars, but at thesame time the power of MOST network also increasing greatly. This has demanded more andmore for car's battery, and has increased automobile fuel consumption, which indirectlyweakened the car's main function. In the energy limited conditions, low energy consumptionof MOST has become equally important with improve performance, reduce cost for designgoal. Therefore, efficient power management design has become indispensable part of MOSTnetworks' design.This paper was developed on the base of project "dynamic power management problemsresearch on MOST networks" form science and technology plan projects in Jilin province.The design and implementation were completed from overall solutions to the hardware andsoftware.The advantage and disadvantage were analyzed the switch power management,centralized power management and distributed power management. So we knew that the power management based on news driven should adopt the distributed structure. Through theanalysis of overtime, forecasting and random DPM algorithms' characteristics, finally chosenthe strategy overtime for the current MOST system.After compared the power consumption, resource allocation and packaging, compatibilityand so on, we have chosen ATmega644as the controller of power management module.According to the demand, its periphery interface circuit was designed, including thecommunication and control interface. Final the hardware design and PCB were completed.Power management module mainly realizes two functions, the salve node manages ownstate and the master node management manages the state of whole network. So the softwarerealization was divided into two main parts: the program of node' EHC and the managementprogram of power management module ATmega644. The EHC section contains port massageinterpreter module, node status notification service module and ATmega128sleep executivemodule. Power management module programs contains initial design of ATmega644,implementation sleep command, the main program of controllable power LDO and theawakening interruption program modules.Finally in tests, through the normal interpreter work, returned event type by EHC, powermanagement module can make sleep or awaken decisions. Whether own state of single nodemanagement or the whole system management of MOST, intended purposes were achieved.The simulation also predicted energy saving trend in more nodes system.The innovation of this paper is that the distributed power management plan based onevents types was put forward and implemented. It solved the problem of waste energy inmany nodes system effectively, perfected the MOST technology application in practice. Nowthe domestic research on MOST technology is just starting and there is not independentintellectual property of the MOST equipment or development platform for the situation. ForMOST technology research and practical application in our country, this paper is far-reachingsignificance.