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1、第六章MCS 51 单片机存储器的扩展 MCS-51单片机内部有 4KB的程序存储器(8031 除外)和 128B数据存储器。在实用中往往不够用，必须加以扩展。而8031 没有内部的程序存储器也必须通过扩展才能使用。在扩展时采用了外部三总线结构：地址总线、数据总线、控制总线。它们分别传递各自的信息。一、地址总线（16 根）1、P0口传递低 8 位地址信息(A7A0)；2、P2口传递高 8 位地址信息(A15A8)。二、数据总线（8 根）P0口传递 8 位数据信息（分时传送）。三、控制总线（5 根）1、程序存储器 读控制信号为PSEN；2、数据存储器的 读控制信号RD或写控制信号 WR；3、地址
2、锁存控制信号为ALE；4、片内/片外选择信号为EA。4-1 程序存储器的扩展一、外部存储器与单片机的连接原理1、内、外部存储器的地址分配 内部程序存储器的地址为0000H 0FFFH；当EA=1时：内、外存储器地址相接，内部从0000H 0FFFH，外部从 1000H 0FFFFH，内外连成一个整体；当EA=0 时：只有外存储器能使用，其地址从0000H 0FFFFH。二、外部存储器与单片机的连接框图1、由 ALE提供选通信号，控制地址锁存器，使P0 口分时传送地址或数据信息。2、P2口直接与程序存储器的高8 位地址相连。3、PSEN与OE相连，控制程序存储器中8 位数据的读操作。三、外部程序
3、存储器 读周期的时序图1、ALE(地址锁存信号)在一个程序存储器读周期内两次有效；2、在 ALE第 1 个下降沿将 P0口输出的低 8 位地址存入地址锁存器；文档编码:CX5Q8Z4Q8R5 HK2E9D8U10U1 ZO9H8A8G7W3文档编码:CX5Q8Z4Q8R5 HK2E9D8U10U1 ZO9H8A8G7W3文档编码:CX5Q8Z4Q8R5 HK2E9D8U10U1 ZO9H8A8G7W3文档编码:CX5Q8Z4Q8R5 HK2E9D8U10U1 ZO9H8A8G7W3文档编码:CX5Q8Z4Q8R5 HK2E9D8U10U1 ZO9H8A8G7W3文档编码:CX5Q8Z4Q8R5
4、 HK2E9D8U10U1 ZO9H8A8G7W3文档编码:CX5Q8Z4Q8R5 HK2E9D8U10U1 ZO9H8A8G7W3文档编码:CX5Q8Z4Q8R5 HK2E9D8U10U1 ZO9H8A8G7W3文档编码:CX5Q8Z4Q8R5 HK2E9D8U10U1 ZO9H8A8G7W3文档编码:CX5Q8Z4Q8R5 HK2E9D8U10U1 ZO9H8A8G7W3文档编码:CX5Q8Z4Q8R5 HK2E9D8U10U1 ZO9H8A8G7W3文档编码:CX5Q8Z4Q8R5 HK2E9D8U10U1 ZO9H8A8G7W3文档编码:CX5Q8Z4Q8R5 HK2E9D8U10U1
5、 ZO9H8A8G7W3文档编码:CX5Q8Z4Q8R5 HK2E9D8U10U1 ZO9H8A8G7W3文档编码:CX5Q8Z4Q8R5 HK2E9D8U10U1 ZO9H8A8G7W3文档编码:CX5Q8Z4Q8R5 HK2E9D8U10U1 ZO9H8A8G7W3文档编码:CX5Q8Z4Q8R5 HK2E9D8U10U1 ZO9H8A8G7W3文档编码:CX5Q8Z4Q8R5 HK2E9D8U10U1 ZO9H8A8G7W3文档编码:CX5Q8Z4Q8R5 HK2E9D8U10U1 ZO9H8A8G7W3文档编码:CX5Q8Z4Q8R5 HK2E9D8U10U1 ZO9H8A8G7W3文
6、档编码:CX5Q8Z4Q8R5 HK2E9D8U10U1 ZO9H8A8G7W3文档编码:CX5Q8Z4Q8R5 HK2E9D8U10U1 ZO9H8A8G7W3文档编码:CX5Q8Z4Q8R5 HK2E9D8U10U1 ZO9H8A8G7W3文档编码:CX5Q8Z4Q8R5 HK2E9D8U10U1 ZO9H8A8G7W3文档编码:CX5Q8Z4Q8R5 HK2E9D8U10U1 ZO9H8A8G7W3文档编码:CX5Q8Z4Q8R5 HK2E9D8U10U1 ZO9H8A8G7W3文档编码:CX5Q8Z4Q8R5 HK2E9D8U10U1 ZO9H8A8G7W3文档编码:CX5Q8Z4Q8
7、R5 HK2E9D8U10U1 ZO9H8A8G7W3文档编码:CX5Q8Z4Q8R5 HK2E9D8U10U1 ZO9H8A8G7W3文档编码:CX5Q8Z4Q8R5 HK2E9D8U10U1 ZO9H8A8G7W3文档编码:CX5Q8Z4Q8R5 HK2E9D8U10U1 ZO9H8A8G7W3文档编码:CX5Q8Z4Q8R5 HK2E9D8U10U1 ZO9H8A8G7W3文档编码:CX5Q8Z4Q8R5 HK2E9D8U10U1 ZO9H8A8G7W3文档编码:CX5Q8Z4Q8R5 HK2E9D8U10U1 ZO9H8A8G7W3文档编码:CX5Q8Z4Q8R5 HK2E9D8U10
8、U1 ZO9H8A8G7W3文档编码:CX5Q8Z4Q8R5 HK2E9D8U10U1 ZO9H8A8G7W3文档编码:CX5Q8Z4Q8R5 HK2E9D8U10U1 ZO9H8A8G7W3文档编码:CX5Q8Z4Q8R5 HK2E9D8U10U1 ZO9H8A8G7W3文档编码:CX5Q8Z4Q8R5 HK2E9D8U10U1 ZO9H8A8G7W3文档编码:CX5Q8Z4Q8R5 HK2E9D8U10U1 ZO9H8A8G7W3文档编码:CX5Q8Z4Q8R5 HK2E9D8U10U1 ZO9H8A8G7W3文档编码:CX5Q8Z4Q8R5 HK2E9D8U10U1 ZO9H8A8G7W
9、3文档编码:CX5Q8Z4Q8R5 HK2E9D8U10U1 ZO9H8A8G7W3文档编码:CX5Q8Z4Q8R5 HK2E9D8U10U1 ZO9H8A8G7W3文档编码:CX5Q8Z4Q8R5 HK2E9D8U10U1 ZO9H8A8G7W3文档编码:CX5Q8Z4Q8R5 HK2E9D8U10U1 ZO9H8A8G7W3文档编码:CX5Q8Z4Q8R5 HK2E9D8U10U1 ZO9H8A8G7W3文档编码:CX5Q8Z4Q8R5 HK2E9D8U10U1 ZO9H8A8G7W33、同时高 8 位地址由 P2口直接送到程序存储器；4、PSEN(程序存储器读控制信号)在低电平时有效，便
10、将数据读出；5、读出的数据通过P0口送回单片机。四、常用的地址锁存器 74LS373是一个典型的 TTL带三态输出的 8 位地址锁存器。1、74LS373框图及每个锁存位的原理图74LS373地址锁存器有 8 个输入端(D8D1)，8 个输出端(Q1Q8)，1 个输入选通端(G)，1 个三态控制端(OE)，1 个接地端(GND)，1 个电源端(CCV)。2、74LS373的工作原理 当输入选通信号 G=1时，锁存器 Q输出端随 D输入端的变化而变化。(A7A0传送的地址信息可以通过锁存器到达扩展的ROM)当输入选通信号G=0(下降沿)时，锁存器被封锁，Q输出端不再随D输入端的变化而变化，一直保
11、持其封锁值不变。(A7A0传送的是数据信息)G 端的输入选通信号由单片机的ALE端提供。五、常用的程序存储器EPROM 芯片介绍文档编码:CX5Q8Z4Q8R5 HK2E9D8U10U1 ZO9H8A8G7W3文档编码:CX5Q8Z4Q8R5 HK2E9D8U10U1 ZO9H8A8G7W3文档编码:CX5Q8Z4Q8R5 HK2E9D8U10U1 ZO9H8A8G7W3文档编码:CX5Q8Z4Q8R5 HK2E9D8U10U1 ZO9H8A8G7W3文档编码:CX5Q8Z4Q8R5 HK2E9D8U10U1 ZO9H8A8G7W3文档编码:CX5Q8Z4Q8R5 HK2E9D8U10U1 Z
12、O9H8A8G7W3文档编码:CX5Q8Z4Q8R5 HK2E9D8U10U1 ZO9H8A8G7W3文档编码:CX5Q8Z4Q8R5 HK2E9D8U10U1 ZO9H8A8G7W3文档编码:CX5Q8Z4Q8R5 HK2E9D8U10U1 ZO9H8A8G7W3文档编码:CX5Q8Z4Q8R5 HK2E9D8U10U1 ZO9H8A8G7W3文档编码:CX5Q8Z4Q8R5 HK2E9D8U10U1 ZO9H8A8G7W3文档编码:CX5Q8Z4Q8R5 HK2E9D8U10U1 ZO9H8A8G7W3文档编码:CX5Q8Z4Q8R5 HK2E9D8U10U1 ZO9H8A8G7W3文档编
13、码:CX5Q8Z4Q8R5 HK2E9D8U10U1 ZO9H8A8G7W3文档编码:CX5Q8Z4Q8R5 HK2E9D8U10U1 ZO9H8A8G7W3文档编码:CX5Q8Z4Q8R5 HK2E9D8U10U1 ZO9H8A8G7W3文档编码:CX5Q8Z4Q8R5 HK2E9D8U10U1 ZO9H8A8G7W3文档编码:CX5Q8Z4Q8R5 HK2E9D8U10U1 ZO9H8A8G7W3文档编码:CX5Q8Z4Q8R5 HK2E9D8U10U1 ZO9H8A8G7W3文档编码:CX5Q8Z4Q8R5 HK2E9D8U10U1 ZO9H8A8G7W3文档编码:CX5Q8Z4Q8R5
14、 HK2E9D8U10U1 ZO9H8A8G7W3文档编码:CX5Q8Z4Q8R5 HK2E9D8U10U1 ZO9H8A8G7W3文档编码:CX5Q8Z4Q8R5 HK2E9D8U10U1 ZO9H8A8G7W3文档编码:CX5Q8Z4Q8R5 HK2E9D8U10U1 ZO9H8A8G7W3文档编码:CX5Q8Z4Q8R5 HK2E9D8U10U1 ZO9H8A8G7W3文档编码:CX5Q8Z4Q8R5 HK2E9D8U10U1 ZO9H8A8G7W3文档编码:CX5Q8Z4Q8R5 HK2E9D8U10U1 ZO9H8A8G7W3文档编码:CX5Q8Z4Q8R5 HK2E9D8U10U1
15、 ZO9H8A8G7W3文档编码:CX5Q8Z4Q8R5 HK2E9D8U10U1 ZO9H8A8G7W3文档编码:CX5Q8Z4Q8R5 HK2E9D8U10U1 ZO9H8A8G7W3文档编码:CX5Q8Z4Q8R5 HK2E9D8U10U1 ZO9H8A8G7W3文档编码:CX5Q8Z4Q8R5 HK2E9D8U10U1 ZO9H8A8G7W3文档编码:CX5Q8Z4Q8R5 HK2E9D8U10U1 ZO9H8A8G7W3文档编码:CX5Q8Z4Q8R5 HK2E9D8U10U1 ZO9H8A8G7W3文档编码:CX5Q8Z4Q8R5 HK2E9D8U10U1 ZO9H8A8G7W3文
16、档编码:CX5Q8Z4Q8R5 HK2E9D8U10U1 ZO9H8A8G7W3文档编码:CX5Q8Z4Q8R5 HK2E9D8U10U1 ZO9H8A8G7W3文档编码:CX5Q8Z4Q8R5 HK2E9D8U10U1 ZO9H8A8G7W3文档编码:CX5Q8Z4Q8R5 HK2E9D8U10U1 ZO9H8A8G7W3文档编码:CX5Q8Z4Q8R5 HK2E9D8U10U1 ZO9H8A8G7W3文档编码:CX5Q8Z4Q8R5 HK2E9D8U10U1 ZO9H8A8G7W3文档编码:CX5Q8Z4Q8R5 HK2E9D8U10U1 ZO9H8A8G7W3文档编码:CX5Q8Z4Q8
17、R5 HK2E9D8U10U1 ZO9H8A8G7W3文档编码:CX5Q8Z4Q8R5 HK2E9D8U10U1 ZO9H8A8G7W3文档编码:CX5Q8Z4Q8R5 HK2E9D8U10U1 ZO9H8A8G7W3文档编码:CX5Q8Z4Q8R5 HK2E9D8U10U1 ZO9H8A8G7W3文档编码:CX5Q8Z4Q8R5 HK2E9D8U10U1 ZO9H8A8G7W3文档编码:CX5Q8Z4Q8R5 HK2E9D8U10U1 ZO9H8A8G7W3以美国 InteL公司的 2764、27128、27256 这三种 EPROM 芯片最具有代表性。2764 存储容量为 8K8；2712
18、8存储容量为 16K8；27256存储容量为 32K81、结构特点：EPROM(Erasable Programmable Read Only Memory)，是紫外线可擦除的可编程半导体只读存储器。一般以27 开头。都是双列直插式 28 脚封装结构，只是存储容量成倍增加。掉电后信息不会丢失，编程时需要专用的编程器写入。文档编码:CX5Q8Z4Q8R5 HK2E9D8U10U1 ZO9H8A8G7W3文档编码:CX5Q8Z4Q8R5 HK2E9D8U10U1 ZO9H8A8G7W3文档编码:CX5Q8Z4Q8R5 HK2E9D8U10U1 ZO9H8A8G7W3文档编码:CX5Q8Z4Q8R5
19、 HK2E9D8U10U1 ZO9H8A8G7W3文档编码:CX5Q8Z4Q8R5 HK2E9D8U10U1 ZO9H8A8G7W3文档编码:CX5Q8Z4Q8R5 HK2E9D8U10U1 ZO9H8A8G7W3文档编码:CX5Q8Z4Q8R5 HK2E9D8U10U1 ZO9H8A8G7W3文档编码:CX5Q8Z4Q8R5 HK2E9D8U10U1 ZO9H8A8G7W3文档编码:CX5Q8Z4Q8R5 HK2E9D8U10U1 ZO9H8A8G7W3文档编码:CX5Q8Z4Q8R5 HK2E9D8U10U1 ZO9H8A8G7W3文档编码:CX5Q8Z4Q8R5 HK2E9D8U10U1
20、 ZO9H8A8G7W3文档编码:CX5Q8Z4Q8R5 HK2E9D8U10U1 ZO9H8A8G7W3文档编码:CX5Q8Z4Q8R5 HK2E9D8U10U1 ZO9H8A8G7W3文档编码:CX5Q8Z4Q8R5 HK2E9D8U10U1 ZO9H8A8G7W3文档编码:CX5Q8Z4Q8R5 HK2E9D8U10U1 ZO9H8A8G7W3文档编码:CX5Q8Z4Q8R5 HK2E9D8U10U1 ZO9H8A8G7W3文档编码:CX5Q8Z4Q8R5 HK2E9D8U10U1 ZO9H8A8G7W3文档编码:CX5Q8Z4Q8R5 HK2E9D8U10U1 ZO9H8A8G7W3文
21、档编码:CX5Q8Z4Q8R5 HK2E9D8U10U1 ZO9H8A8G7W3文档编码:CX5Q8Z4Q8R5 HK2E9D8U10U1 ZO9H8A8G7W3文档编码:CX5Q8Z4Q8R5 HK2E9D8U10U1 ZO9H8A8G7W3文档编码:CX5Q8Z4Q8R5 HK2E9D8U10U1 ZO9H8A8G7W3文档编码:CX5Q8Z4Q8R5 HK2E9D8U10U1 ZO9H8A8G7W3文档编码:CX5Q8Z4Q8R5 HK2E9D8U10U1 ZO9H8A8G7W3文档编码:CX5Q8Z4Q8R5 HK2E9D8U10U1 ZO9H8A8G7W3文档编码:CX5Q8Z4Q8
22、R5 HK2E9D8U10U1 ZO9H8A8G7W3文档编码:CX5Q8Z4Q8R5 HK2E9D8U10U1 ZO9H8A8G7W3文档编码:CX5Q8Z4Q8R5 HK2E9D8U10U1 ZO9H8A8G7W3文档编码:CX5Q8Z4Q8R5 HK2E9D8U10U1 ZO9H8A8G7W3文档编码:CX5Q8Z4Q8R5 HK2E9D8U10U1 ZO9H8A8G7W3文档编码:CX5Q8Z4Q8R5 HK2E9D8U10U1 ZO9H8A8G7W3文档编码:CX5Q8Z4Q8R5 HK2E9D8U10U1 ZO9H8A8G7W3文档编码:CX5Q8Z4Q8R5 HK2E9D8U10
23、U1 ZO9H8A8G7W3文档编码:CX5Q8Z4Q8R5 HK2E9D8U10U1 ZO9H8A8G7W3文档编码:CX5Q8Z4Q8R5 HK2E9D8U10U1 ZO9H8A8G7W3文档编码:CX5Q8Z4Q8R5 HK2E9D8U10U1 ZO9H8A8G7W3文档编码:CX5Q8Z4Q8R5 HK2E9D8U10U1 ZO9H8A8G7W3文档编码:CX5Q8Z4Q8R5 HK2E9D8U10U1 ZO9H8A8G7W3文档编码:CX5Q8Z4Q8R5 HK2E9D8U10U1 ZO9H8A8G7W3文档编码:CX5Q8Z4Q8R5 HK2E9D8U10U1 ZO9H8A8G7W
24、3文档编码:CX5Q8Z4Q8R5 HK2E9D8U10U1 ZO9H8A8G7W3文档编码:CX5Q8Z4Q8R5 HK2E9D8U10U1 ZO9H8A8G7W3文档编码:CX5Q8Z4Q8R5 HK2E9D8U10U1 ZO9H8A8G7W3文档编码:CX5Q8Z4Q8R5 HK2E9D8U10U1 ZO9H8A8G7W3文档编码:CX5Q8Z4Q8R5 HK2E9D8U10U1 ZO9H8A8G7W3文档编码:CX5Q8Z4Q8R5 HK2E9D8U10U1 ZO9H8A8G7W3文档编码:CX5Q8Z4Q8R5 HK2E9D8U10U1 ZO9H8A8G7W3文档编码:CX5Q8Z4
25、Q8R5 HK2E9D8U10U1 ZO9H8A8G7W32、引脚功能：2764、27128和 27256主电源脚都为 Vcc(+5V)，都有公共地端(GND)；它们的编程电源引脚都为Vpp；2764 地址信号线为 A12 A0，共有 13 根，KB8213；27128地址信号线为 A13A0，共有 14 根，KB16214；27256地址信号线为 A14A0，共有 15 根，KB32215。它们的数据信号线为O7O0，共有 8 根；CE 为片选通信号输入端，CE=0时该芯片被选中，CE=1 时该芯片不被选中。OE为允许数据输出(读)选通信号输入端，低电平有效。PGM 为编程脉冲输入端。仅在编
26、程时接收编程脉冲。六、程序存储器扩展电路(用 8031 单片机与 EPROM27256 配套为例)1、P0口的 3932 脚输出的 8 位信号。并分为两路。一路作为地址总线送74LS373地址锁存器，为 27256提供低 8 位地址信文档编码:CX5Q8Z4Q8R5 HK2E9D8U10U1 ZO9H8A8G7W3文档编码:CX5Q8Z4Q8R5 HK2E9D8U10U1 ZO9H8A8G7W3文档编码:CX5Q8Z4Q8R5 HK2E9D8U10U1 ZO9H8A8G7W3文档编码:CX5Q8Z4Q8R5 HK2E9D8U10U1 ZO9H8A8G7W3文档编码:CX5Q8Z4Q8R5 HK
27、2E9D8U10U1 ZO9H8A8G7W3文档编码:CX5Q8Z4Q8R5 HK2E9D8U10U1 ZO9H8A8G7W3文档编码:CX5Q8Z4Q8R5 HK2E9D8U10U1 ZO9H8A8G7W3文档编码:CX5Q8Z4Q8R5 HK2E9D8U10U1 ZO9H8A8G7W3文档编码:CX5Q8Z4Q8R5 HK2E9D8U10U1 ZO9H8A8G7W3文档编码:CX5Q8Z4Q8R5 HK2E9D8U10U1 ZO9H8A8G7W3文档编码:CX5Q8Z4Q8R5 HK2E9D8U10U1 ZO9H8A8G7W3文档编码:CX5Q8Z4Q8R5 HK2E9D8U10U1 ZO
28、9H8A8G7W3文档编码:CX5Q8Z4Q8R5 HK2E9D8U10U1 ZO9H8A8G7W3文档编码:CX5Q8Z4Q8R5 HK2E9D8U10U1 ZO9H8A8G7W3文档编码:CX5Q8Z4Q8R5 HK2E9D8U10U1 ZO9H8A8G7W3文档编码:CX5Q8Z4Q8R5 HK2E9D8U10U1 ZO9H8A8G7W3文档编码:CX5Q8Z4Q8R5 HK2E9D8U10U1 ZO9H8A8G7W3文档编码:CX5Q8Z4Q8R5 HK2E9D8U10U1 ZO9H8A8G7W3文档编码:CX5Q8Z4Q8R5 HK2E9D8U10U1 ZO9H8A8G7W3文档编码
29、:CX5Q8Z4Q8R5 HK2E9D8U10U1 ZO9H8A8G7W3文档编码:CX5Q8Z4Q8R5 HK2E9D8U10U1 ZO9H8A8G7W3文档编码:CX5Q8Z4Q8R5 HK2E9D8U10U1 ZO9H8A8G7W3文档编码:CX5Q8Z4Q8R5 HK2E9D8U10U1 ZO9H8A8G7W3文档编码:CX5Q8Z4Q8R5 HK2E9D8U10U1 ZO9H8A8G7W3文档编码:CX5Q8Z4Q8R5 HK2E9D8U10U1 ZO9H8A8G7W3文档编码:CX5Q8Z4Q8R5 HK2E9D8U10U1 ZO9H8A8G7W3文档编码:CX5Q8Z4Q8R5
30、HK2E9D8U10U1 ZO9H8A8G7W3文档编码:CX5Q8Z4Q8R5 HK2E9D8U10U1 ZO9H8A8G7W3文档编码:CX5Q8Z4Q8R5 HK2E9D8U10U1 ZO9H8A8G7W3文档编码:CX5Q8Z4Q8R5 HK2E9D8U10U1 ZO9H8A8G7W3文档编码:CX5Q8Z4Q8R5 HK2E9D8U10U1 ZO9H8A8G7W3文档编码:CX5Q8Z4Q8R5 HK2E9D8U10U1 ZO9H8A8G7W3文档编码:CX5Q8Z4Q8R5 HK2E9D8U10U1 ZO9H8A8G7W3文档编码:CX5Q8Z4Q8R5 HK2E9D8U10U1
31、ZO9H8A8G7W3文档编码:CX5Q8Z4Q8R5 HK2E9D8U10U1 ZO9H8A8G7W3文档编码:CX5Q8Z4Q8R5 HK2E9D8U10U1 ZO9H8A8G7W3文档编码:CX5Q8Z4Q8R5 HK2E9D8U10U1 ZO9H8A8G7W3文档编码:CX5Q8Z4Q8R5 HK2E9D8U10U1 ZO9H8A8G7W3文档编码:CX5Q8Z4Q8R5 HK2E9D8U10U1 ZO9H8A8G7W3文档编码:CX5Q8Z4Q8R5 HK2E9D8U10U1 ZO9H8A8G7W3文档编码:CX5Q8Z4Q8R5 HK2E9D8U10U1 ZO9H8A8G7W3文档
32、编码:CX5Q8Z4Q8R5 HK2E9D8U10U1 ZO9H8A8G7W3文档编码:CX5Q8Z4Q8R5 HK2E9D8U10U1 ZO9H8A8G7W3文档编码:CX5Q8Z4Q8R5 HK2E9D8U10U1 ZO9H8A8G7W3文档编码:CX5Q8Z4Q8R5 HK2E9D8U10U1 ZO9H8A8G7W3文档编码:CX5Q8Z4Q8R5 HK2E9D8U10U1 ZO9H8A8G7W3文档编码:CX5Q8Z4Q8R5 HK2E9D8U10U1 ZO9H8A8G7W3文档编码:CX5Q8Z4Q8R5 HK2E9D8U10U1 ZO9H8A8G7W3号。另一路作为数据总线，直接与
33、27256相连接用于 8 位数据信号的读取。2、P2口的 2128 脚输出的 8 位信号。(具体连接如下)2127 脚直接与 27256 的 A14A8相连接，提供了高7 位地址信号。28 脚直接与 27256 的CE相连接：(功能如下)当 28 脚为 0 时,即：P2.7=0，27256被选通,地址范围是 0000H 7FFFH。当 28 脚为 1 时,即：P2.7=1，27256未被选通，不工作。3、地址锁存信号 ALE与 74LS373地址锁存器输入选通端G相连，用于锁存P0口的送出的低 8 位地址信号。4、读选通信号PSEN与 27256的OE相连，用于读取数据。4-2 数据存储器的扩
34、展一、MCS-51单片机扩展数据存储器结构图文档编码:CX5Q8Z4Q8R5 HK2E9D8U10U1 ZO9H8A8G7W3文档编码:CX5Q8Z4Q8R5 HK2E9D8U10U1 ZO9H8A8G7W3文档编码:CX5Q8Z4Q8R5 HK2E9D8U10U1 ZO9H8A8G7W3文档编码:CX5Q8Z4Q8R5 HK2E9D8U10U1 ZO9H8A8G7W3文档编码:CX5Q8Z4Q8R5 HK2E9D8U10U1 ZO9H8A8G7W3文档编码:CX5Q8Z4Q8R5 HK2E9D8U10U1 ZO9H8A8G7W3文档编码:CX5Q8Z4Q8R5 HK2E9D8U10U1 ZO
35、9H8A8G7W3文档编码:CX5Q8Z4Q8R5 HK2E9D8U10U1 ZO9H8A8G7W3文档编码:CX5Q8Z4Q8R5 HK2E9D8U10U1 ZO9H8A8G7W3文档编码:CX5Q8Z4Q8R5 HK2E9D8U10U1 ZO9H8A8G7W3文档编码:CX5Q8Z4Q8R5 HK2E9D8U10U1 ZO9H8A8G7W3文档编码:CX5Q8Z4Q8R5 HK2E9D8U10U1 ZO9H8A8G7W3文档编码:CX5Q8Z4Q8R5 HK2E9D8U10U1 ZO9H8A8G7W3文档编码:CX5Q8Z4Q8R5 HK2E9D8U10U1 ZO9H8A8G7W3文档编码
36、:CX5Q8Z4Q8R5 HK2E9D8U10U1 ZO9H8A8G7W3文档编码:CX5Q8Z4Q8R5 HK2E9D8U10U1 ZO9H8A8G7W3文档编码:CX5Q8Z4Q8R5 HK2E9D8U10U1 ZO9H8A8G7W3文档编码:CX5Q8Z4Q8R5 HK2E9D8U10U1 ZO9H8A8G7W3文档编码:CX5Q8Z4Q8R5 HK2E9D8U10U1 ZO9H8A8G7W3文档编码:CX5Q8Z4Q8R5 HK2E9D8U10U1 ZO9H8A8G7W3文档编码:CX5Q8Z4Q8R5 HK2E9D8U10U1 ZO9H8A8G7W3文档编码:CX5Q8Z4Q8R5
37、HK2E9D8U10U1 ZO9H8A8G7W3文档编码:CX5Q8Z4Q8R5 HK2E9D8U10U1 ZO9H8A8G7W3文档编码:CX5Q8Z4Q8R5 HK2E9D8U10U1 ZO9H8A8G7W3文档编码:CX5Q8Z4Q8R5 HK2E9D8U10U1 ZO9H8A8G7W3文档编码:CX5Q8Z4Q8R5 HK2E9D8U10U1 ZO9H8A8G7W3文档编码:CX5Q8Z4Q8R5 HK2E9D8U10U1 ZO9H8A8G7W3文档编码:CX5Q8Z4Q8R5 HK2E9D8U10U1 ZO9H8A8G7W3文档编码:CX5Q8Z4Q8R5 HK2E9D8U10U1
38、ZO9H8A8G7W3文档编码:CX5Q8Z4Q8R5 HK2E9D8U10U1 ZO9H8A8G7W3文档编码:CX5Q8Z4Q8R5 HK2E9D8U10U1 ZO9H8A8G7W3文档编码:CX5Q8Z4Q8R5 HK2E9D8U10U1 ZO9H8A8G7W3文档编码:CX5Q8Z4Q8R5 HK2E9D8U10U1 ZO9H8A8G7W3文档编码:CX5Q8Z4Q8R5 HK2E9D8U10U1 ZO9H8A8G7W3文档编码:CX5Q8Z4Q8R5 HK2E9D8U10U1 ZO9H8A8G7W3文档编码:CX5Q8Z4Q8R5 HK2E9D8U10U1 ZO9H8A8G7W3文档
39、编码:CX5Q8Z4Q8R5 HK2E9D8U10U1 ZO9H8A8G7W3文档编码:CX5Q8Z4Q8R5 HK2E9D8U10U1 ZO9H8A8G7W3文档编码:CX5Q8Z4Q8R5 HK2E9D8U10U1 ZO9H8A8G7W3文档编码:CX5Q8Z4Q8R5 HK2E9D8U10U1 ZO9H8A8G7W3文档编码:CX5Q8Z4Q8R5 HK2E9D8U10U1 ZO9H8A8G7W3文档编码:CX5Q8Z4Q8R5 HK2E9D8U10U1 ZO9H8A8G7W3文档编码:CX5Q8Z4Q8R5 HK2E9D8U10U1 ZO9H8A8G7W3文档编码:CX5Q8Z4Q8R
40、5 HK2E9D8U10U1 ZO9H8A8G7W3文档编码:CX5Q8Z4Q8R5 HK2E9D8U10U1 ZO9H8A8G7W3文档编码:CX5Q8Z4Q8R5 HK2E9D8U10U1 ZO9H8A8G7W3文档编码:CX5Q8Z4Q8R5 HK2E9D8U10U1 ZO9H8A8G7W3文档编码:CX5Q8Z4Q8R5 HK2E9D8U10U1 ZO9H8A8G7W31、P0 口通过 8 位地址锁存器向外部数据存储器分时提供低8 位地址信息和8 位数据信息；2、单片机地址锁存信号ALE为 8 位地址锁存器提供选通信号；3、P2口向外部数据存储器提供高8 位地址；4、P2口提供一个信号
41、给译码器译码，用以得到RAM 的片选信号；5、单片机读信号端RD可直接向数据存储器OE端发“读”命令，使信息从外部数据存储器经P0口数据总线进入单片机；6、单片机写信号端WR可直接向数据存储器WE端发“写”命令，使信息从单片机经 P0口数据总线进入外部数据存储器。二、外部数据存储器读/写周期时序图文档编码:CX5Q8Z4Q8R5 HK2E9D8U10U1 ZO9H8A8G7W3文档编码:CX5Q8Z4Q8R5 HK2E9D8U10U1 ZO9H8A8G7W3文档编码:CX5Q8Z4Q8R5 HK2E9D8U10U1 ZO9H8A8G7W3文档编码:CX5Q8Z4Q8R5 HK2E9D8U10U
42、1 ZO9H8A8G7W3文档编码:CX5Q8Z4Q8R5 HK2E9D8U10U1 ZO9H8A8G7W3文档编码:CX5Q8Z4Q8R5 HK2E9D8U10U1 ZO9H8A8G7W3文档编码:CX5Q8Z4Q8R5 HK2E9D8U10U1 ZO9H8A8G7W3文档编码:CX5Q8Z4Q8R5 HK2E9D8U10U1 ZO9H8A8G7W3文档编码:CX5Q8Z4Q8R5 HK2E9D8U10U1 ZO9H8A8G7W3文档编码:CX5Q8Z4Q8R5 HK2E9D8U10U1 ZO9H8A8G7W3文档编码:CX5Q8Z4Q8R5 HK2E9D8U10U1 ZO9H8A8G7W3
43、文档编码:CX5Q8Z4Q8R5 HK2E9D8U10U1 ZO9H8A8G7W3文档编码:CX5Q8Z4Q8R5 HK2E9D8U10U1 ZO9H8A8G7W3文档编码:CX5Q8Z4Q8R5 HK2E9D8U10U1 ZO9H8A8G7W3文档编码:CX5Q8Z4Q8R5 HK2E9D8U10U1 ZO9H8A8G7W3文档编码:CX5Q8Z4Q8R5 HK2E9D8U10U1 ZO9H8A8G7W3文档编码:CX5Q8Z4Q8R5 HK2E9D8U10U1 ZO9H8A8G7W3文档编码:CX5Q8Z4Q8R5 HK2E9D8U10U1 ZO9H8A8G7W3文档编码:CX5Q8Z4Q
44、8R5 HK2E9D8U10U1 ZO9H8A8G7W3文档编码:CX5Q8Z4Q8R5 HK2E9D8U10U1 ZO9H8A8G7W3文档编码:CX5Q8Z4Q8R5 HK2E9D8U10U1 ZO9H8A8G7W3文档编码:CX5Q8Z4Q8R5 HK2E9D8U10U1 ZO9H8A8G7W3文档编码:CX5Q8Z4Q8R5 HK2E9D8U10U1 ZO9H8A8G7W3文档编码:CX5Q8Z4Q8R5 HK2E9D8U10U1 ZO9H8A8G7W3文档编码:CX5Q8Z4Q8R5 HK2E9D8U10U1 ZO9H8A8G7W3文档编码:CX5Q8Z4Q8R5 HK2E9D8U1
45、0U1 ZO9H8A8G7W3文档编码:CX5Q8Z4Q8R5 HK2E9D8U10U1 ZO9H8A8G7W3文档编码:CX5Q8Z4Q8R5 HK2E9D8U10U1 ZO9H8A8G7W3文档编码:CX5Q8Z4Q8R5 HK2E9D8U10U1 ZO9H8A8G7W3文档编码:CX5Q8Z4Q8R5 HK2E9D8U10U1 ZO9H8A8G7W3文档编码:CX5Q8Z4Q8R5 HK2E9D8U10U1 ZO9H8A8G7W3文档编码:CX5Q8Z4Q8R5 HK2E9D8U10U1 ZO9H8A8G7W3文档编码:CX5Q8Z4Q8R5 HK2E9D8U10U1 ZO9H8A8G7
46、W3文档编码:CX5Q8Z4Q8R5 HK2E9D8U10U1 ZO9H8A8G7W3文档编码:CX5Q8Z4Q8R5 HK2E9D8U10U1 ZO9H8A8G7W3文档编码:CX5Q8Z4Q8R5 HK2E9D8U10U1 ZO9H8A8G7W3文档编码:CX5Q8Z4Q8R5 HK2E9D8U10U1 ZO9H8A8G7W3文档编码:CX5Q8Z4Q8R5 HK2E9D8U10U1 ZO9H8A8G7W3文档编码:CX5Q8Z4Q8R5 HK2E9D8U10U1 ZO9H8A8G7W3文档编码:CX5Q8Z4Q8R5 HK2E9D8U10U1 ZO9H8A8G7W3文档编码:CX5Q8Z
47、4Q8R5 HK2E9D8U10U1 ZO9H8A8G7W3文档编码:CX5Q8Z4Q8R5 HK2E9D8U10U1 ZO9H8A8G7W3文档编码:CX5Q8Z4Q8R5 HK2E9D8U10U1 ZO9H8A8G7W3文档编码:CX5Q8Z4Q8R5 HK2E9D8U10U1 ZO9H8A8G7W3文档编码:CX5Q8Z4Q8R5 HK2E9D8U10U1 ZO9H8A8G7W3文档编码:CX5Q8Z4Q8R5 HK2E9D8U10U1 ZO9H8A8G7W3文档编码:CX5Q8Z4Q8R5 HK2E9D8U10U1 ZO9H8A8G7W3文档编码:CX5Q8Z4Q8R5 HK2E9D8
48、U10U1 ZO9H8A8G7W31、外部数据存储器读周期时序 在地址锁存信号 ALE下降沿，P0口输出的低 8 位地址 A7A0被锁存；P2 口此时也将高 8 位地址直接送出；读控制信号RD(低电平有效)到来，数据就从数据存储器中被读了出来；读出来的数据经过P0口输入到单片机中，完成了一次读操作工作。2、外部数据存储器写周期时序 在地址锁存信号 ALE下降沿，P0口输出的低 8 位地址 A7A0被锁存；P2 口此时也将高 8 位地址直接送出；写控制信号WR(低电平有效)到来，数据就从单片机中被写出来；写出来的数据经过P0口输出到数据存储器中，完成了一次写操作工作。三、常用数据存储器RAM 芯
49、片介绍外部数据存储器也称静态随机存储器RAM，常用的有6116、6264 两种芯片。它们都是双列直插式封装结构。1、6116 芯片(24 脚)文档编码:CX5Q8Z4Q8R5 HK2E9D8U10U1 ZO9H8A8G7W3文档编码:CX5Q8Z4Q8R5 HK2E9D8U10U1 ZO9H8A8G7W3文档编码:CX5Q8Z4Q8R5 HK2E9D8U10U1 ZO9H8A8G7W3文档编码:CX5Q8Z4Q8R5 HK2E9D8U10U1 ZO9H8A8G7W3文档编码:CX5Q8Z4Q8R5 HK2E9D8U10U1 ZO9H8A8G7W3文档编码:CX5Q8Z4Q8R5 HK2E9D8
50、U10U1 ZO9H8A8G7W3文档编码:CX5Q8Z4Q8R5 HK2E9D8U10U1 ZO9H8A8G7W3文档编码:CX5Q8Z4Q8R5 HK2E9D8U10U1 ZO9H8A8G7W3文档编码:CX5Q8Z4Q8R5 HK2E9D8U10U1 ZO9H8A8G7W3文档编码:CX5Q8Z4Q8R5 HK2E9D8U10U1 ZO9H8A8G7W3文档编码:CX5Q8Z4Q8R5 HK2E9D8U10U1 ZO9H8A8G7W3文档编码:CX5Q8Z4Q8R5 HK2E9D8U10U1 ZO9H8A8G7W3文档编码:CX5Q8Z4Q8R5 HK2E9D8U10U1 ZO9H8A8