External Program Memory的意思|示意

This tiny program is a bootloader that will initialize the attached memory controllers, possibly load the main program from some external source, and jump to it.

该小程序是一个bootloader，可以初始化附带的内存控制器，可能从某些外部源载入主程序，然后跳入主程序。

Running the program from external storage memory is not advised since when connected to PC the external card could be unrecognizable by the system.

运行程序从外部存储内存不建议，因为当连接到PC的外部卡可以被系统认不出来。

Port 0 is also the multiplexed low-order address and data bus during access to external program and data memory.

端口0也是复低位地址和在利用外部程序和数据存储器的数据总线。

Thedownloading program receives the new application program and loads it into a readonly memory external to the microcontroller.

装载程序接收新的应用程序并存储到单片机的外部 ROM 中。