单片机(黄英)：第5章 单片机并行存储器扩展 双语教学_黄英_《单片机原理和应用》讲义.ppt

Chapter 5 :  Memory extension;Contents: ;5.1 Memory extension introduction;5.1.1 System extension and it’s structure;· Extension objects: ROM, RAM, I/O interface circuit, etc. ;· In order to realize system extension, the first thing is:;2. System Bus its construction method;① Address Bus（AB）;② Data Bus（DB） ;③ Control Bus（CB） ;（2）System Bus Construction;Fig. 2 Construction Diagram of System Bus Extension;5.1.2 Memory extension addresses arrangement ;1. Memory System of Microcontroller;2. Address Searching Technology of Memory Extension ;（1） Line-Selection Method · Uses address line directly. · Suitable for expanding memory in small scale. ;（2） Encoding Method · Uses encoder to produce chip-selection signal. ① Dual 2-4 encoder: 74LS139 ② 3-8 encoder: 74LS138 · Suitable for expanding memory in large scale. ;5.2 Program memory extension ;5.2.1 Read Only Memory（ROM）;5.2.2 Typical Extension Chip of Program Memory ; Fig.4 Pins Arrangement of 2716 ;2. Working Modes of EPROM 2716 ;5.2.3 Extension examples of Program Memory ;1. Single Chip Extension ;Fig. 5 Single Chip Extension of Program Memory;There are 16 overlap areas（mapping areas）: ∵ P2.6～P2.3 = 0000～FFFF， 24 =16;2. Multi-Chip Extension ;Fig. 6 Multi-Chip Extension of Program Memory ;Address Arrangement: Chip #1: 0000H ～ 1FFFH, Chip #2: 8000H ～ 9FFFH ;5.3 Data memory extension ;5.3.1 Random-Access Memory（RAM） ;5.3.2 Typical Extension Chip of Data Memory ; Pins Arrangement of SRAM 6116（2KB×8）;2. Working Modes of SRAM 6116 ;5.3.3 Examples of Extension Data Memory ;· 6116（2KB×8） 211 → A10～A0 → 23×28 → P2.2～P2.0 → P0.7～P0.0 ;Fig. 8 Single Chip Extension of Data Memory ;Address Arrangement: 0000H ～ 07FFH ;2. Multi-Chip Expanding ;（1）Adopts: Line-Selection Method;Fig. 9 Multi-Chip Extension of Data Memory ;Address Arrangement: Chip #1: 7000H ～ 77FFH Chip #2: 6800H ～ 6FFFH Chip #3: 5800H ～ 5FFFH Chip #4: 3800H ～ 3FFFH;（2）Adopts: Encoding Me