Research Of Key Technologies Of Onboard Mass Storage Based On EMMC

With the development of space exploration and the diversity of mission requirements,the demand for storage capacity and bandwidth of image payloads is getting higher.With the development of technology,on-board storage media has experienced transition from magnetic media to semiconductor media,currently Flash is widely used.However,due to the complex interface and operation protocol and higher probability appearing broken blocks,Flash is developed with high development costs and long cycle needed.In view of the above problems,a program is proposed that use eMMC to build a large-capacity storage,whose key technology research is carried out as follows.Initially,this paper analyzes the development trend of on-board storage through investigation of large-capacity storage around the world.Meanwhile,a survey towards the fault-tolerant technology is also performed for the space radiation environment faced by the on-board equipment,mainly for the fault-tolerant design and protection technology for single event upset effect and single event latch-up effect.Based on the analysis of features of eMMC,two key technologies are proposed,namely eMMC storage array access control technology and fault-tolerant reinforcement technology for on-board memory based on eMMC.System environment on key research is also established.Secondly,before the implementation of eMMC array storage access control technology,the eMMC 5.0 specification is studied in detail.On this basis,FPGA is used as the main controller,and the eMMC interface control logic is designed and implemented.At the same time,eMMC read-write scheduling is designed for read-write access of upper application.Because of different delay among eMMC array,eMMC array synchronization technology is proposed.Thirdly,in view of the space radiation environment faced by eMMC devices and control systems,this paper presents a fault-tolerant reinforcement technology against single event upset effect,mainly for fault-tolerant reinforcement of eMMC main controller,moreover,a FIFO fault-tolerant technology based on extended Hamming code and fault-tolerant reinforcement technology for TMR state machine is also proposed.A single event latch-up protection circuit is proposed and designed in detail according to the characteristics of the latch-up of the circuit.Finally,an experimental test and verification scheme is proposed for above key technologies.The board-level test method for eMMC access and control technology is used to measure the read-write functions.A test under the circumstance of failure injection is proposed for the fault-tolerant design of single event upset effect and single event latch-up protection circuit.Test results show that the design meets the target.The research of the key technology of large-capacity storage based on eMMC in this paper will provide substantial support for the subsequent practical engineering applications.