Stable And Reliable Software Upgrade Design For Set Top Box Embedded System Software

Embedded system technique has been developed rapidly with the development of new information technologies. Embedded devices has been widely applied to many fields such as consumer electronics, network communications, industrial control and etc., due to its attractive features including smaller size, stronger performance, lower power consumption, and higher reliability for industrial applications. Almost all home electronic appliances, such as digital TV set-top boxes, mobile phones, multimedia devices, automobiles, microwave ovens, digital cameras, home automation systems, elevators, security systems, cellular phones, industrial automation, and medical instruments are built in with the embedded system. Information appliances with computer technology, communication technology, semiconductor technology, data transmission processing technology or sensor technology have become the most important application area of embedded system. This topic in this thesis is focused on digital TV set-top box, a typical application of embedded system.This thesis concentrated on embedded software system upgrading methodology in digital TV set-top box. Its purpose is to provide a complete solution to solve practical problems encountered when upgrading set-top box, to prevent the possibility of generating data confusion, interfaces and operation methods inconsistency. These issues are the root cause to disrupting management and maintenance. Traditional set-top boxes were such designed that only part of the application could be upgradeable, while loader itself could not be updated. Once some hardware parts are to be changed, boxes containing the old version of software could no longer be compatible or upgraded. In this case, software for new models of STB has to be developed and maintained as a remedy for the same market although they shared the same functionality. As a result, errors come out more frequently than we expect. Otherwise, the common hardware parts as tuner,flash,EEPROM models are limited to be selected in manufacturing. In this thesis, a new algorithm is proposed that the program code is stored in the flash with several parts so that set-top box embedded system software upgrade can be done with more flexibly. The hardware drivers in loader are designed to provide maximum compatibility with two kinds of upgrade methods, i.e. automatic and manually.In this thesis the upgrade of program in the cable set-top box is studied. It provides a total upgrade solution covering software structural design, data storage algorithm, and safe procedure design. The upgrade through the cable can automatically update the code, or user can manually upgrade the code. Some set-top boxes can also be automatically or manually upgraded through the network, USB or UART. The general manually upgrade method based on data transmission from UART (RS-232). CRC32 algorithm is introduced to verify the integrity of the code, and the MD5 algorithm to ensure data reliability are used in this research.This solution solves the upgrade restrictions on set-top box which makes upgrade and maintenance of the different manufacturer's set-top box easily. And the forward compatible hardware design can save upgrade costs too.