1设计思想MC-51系列单片机对程序存储器的基本寻址能力最大为64kb，这时共需要16根地址线，其中低8位由PO口提供，高8位由P2口提供。若欲寻址更大的存储空间，直接的方法是增加地址线，每增加一条，寻址空间扩大一倍。但是由于单片机的I／O资源有限，靠增加地址线来扩展存储空 1 design ideas MC-51 series of microcontrollers on the program memory basic addressing capacity of up to 64kb, then a total of 16 address lines are required, of which the lower 8 bits provided by the PO port, the upper 8 bits provided by the P2 port. If you want to address the larger storage space, the direct method is to increase the address line, for each additional one, addressing space doubles. However, due to the limited single-chip I / O resources, by increasing the address line to expand memory space