说明：  文档介绍了基于DM642的自启动的FLASH烧写原理研究及实现，详细介绍了FLASH的工作原理、硬件连接方法，DM642的boot原理
(Document based on the DM642 introduction of the FLASH programmer since the launch of the principles of research and implementation, detailing the work of FLASH principle, the hardware connection method, DM642' s boot Principle)