SRAMStatic RAM DRAMDynamic RAM RAM Random Access Memory
- Slides: 19
第一节 存储器扩展概述 一、存储器分类 SRAM(Static RAM) DRAM(Dynamic RAM) RAM (Random Access Memory) 存储器M NVRAM(Non Volative RAM) 掩模ROM (Read Only Memory) PROM(Programable ROM) EPROM(Erasable PROM) E 2 PROM(Electrically EPROM)
二、MCS-51的最小系统 A 8 -A 15 时钟 电路 P 2 ALE P 0 8031 复位 电路 8051 8751 AB 地址 锁存器 A 0 -A 7 D 0 -D 7 /PSEN /WR /RD ROM DB CB 图 8 -2
… … 例 用 2764(8 K*8 bit即 8 KB)扩展 16 K字节的EPROM ?… 对于片选信号有 P 2. 7 A 12 A 11 P 2. 6 以下三种连接方 … … P 2. 5 A 8 /CE 法 P 2. 4 A 7 P 2. 3 … … 2764 P 2. 2 P 2. 1 P 2. 0 8051 P 0. 0 P 0. 1 … O 0 … … O 7 … 74 LS 373 P 0. 7 ALE /PSEN A 0 G /OE A 12 A 11 … … … A 8 A 7 /CE … … 2764 A 0 O 0 …… O 7 /OE
(一)线选法 A 0—A 10 A 11 A 12 /CE #1 #2 A 13 /CE #3 A 14 /CE #4 DB 0 -7 A 15 A 14 A 13 A 12 A 11 A 10 A 8 A 9 A 8 A 7 A 6 A 5 A 4 A 3 A 2 A 1 A 0 #1: * #2: * #3: #4: 1 1 1 0 0 0 0 7000 H 1 1 1 77 FFH 6800 H 6 FFFH 1 5800 H— 5 FFFH 3800 H— 3 FFFH
(二)全译码法 A 0 -A 10 A 0 -A 15 Q 0 5 -32 … 译 Q 3 码 器 … A 11 -A 15 Q 31 /CE #4 /CE #3 /CE #2 #1 DB 0 -7 A 15 A 14 A 13 A 12 A 11 A 10 A 9 A 8 A 7 A 6 A 5 A 4 A 3 A 2 A 1 A 0 1#: 0 2#: 0 3#: 4#: 0 0 0 0 0000 H 1 1 1 1 0800 H----0 FFFH 1000 H----17 FFH 1800 H----1 FFFH 07 FFH
(三)部分译码法 A 0 -A 10 A 0 -A 12 Q 0 2 -4 … 译 Q 3 A 11 -A 12 码 器 /CE #4 /CE #3 #2 /CE #1 DB 0 -7 1#: A 15 A 14 A 13 A 12 A 11 A 10 A 9 A 8 A 7 A 6 A 5 A 4 A 3 A 2 A 1 A 0 * * * 0 0 0 0 0 1 …… 1 1 0000 H 地址重叠 1 1 1 1 1 2000 H … … E 000 H
补例 扩展 16 K字节EPROM P 2. 7 P 2. 6 P 2. 5 P 2. 4 P 2. 3 P 2. 2 P 2. 1 P 2. 0 8051 P 0. 0 P 0. 1 P 0. 2 P 0. 3 /PSEN P 0. 4 P 0. 5 P 0. 6 ALE P 0. 7 74 LS 373 G /CE A 13 A 12 A 11 A 10 A 9 A 8 O 7 O 6 O 5 27128 O 4 O 3 O 2 O 1 O 0 A 1 A 2 A 3 A 4 A 5 A 6 A 7 /OE
补例 线选法扩展 4 KB RAM(6116: 2 K*8 bit) P 2. 4 P 2. 3 P 2. 2 P 2. 1 P 2. 0 8051 P 0. 0 -P 0. 7 ALE /RD /WR 8282 A 10 /CS A 9 A 8 6116 A 0 -A 7 D 0 -D 7 /OE /WE
补例 部分译码法扩展 4 KBRAM P 2. 7 P 2. 6 P 2. 5 P 2. 2 … P 2. 0 ALE P 0. 0 -P 0. 7 8031 /WR /RD 2: 4 /Y 0 /G译 /Y 1 A码 … … B 器 /Y 3 G 74 LS 373 A 0 -A 10 /CE 2#6116 /WE /OE D 7 -D 0 A 0 -A 10 /CE 1#6116 /WE /OE D 7 -D 0 #1: 0000 H— 07 FFH #2: 2000 H— 27 FFH
补例 扩展 2 K字节E 2 PROM P 1. 0 /WR /RD /PSEN 8051 P 2. 7 P 2. 2 P 2. 1 P 2. 0 ALE P 0. 7 -P 0. 0 RDY/BUSY /WE /OE 2817 /CE A 10 A 9 A 8 G 74 LS 373 A 7 -A 0 I/O 0 -I/O 7 地址重叠区 16个。
补例 同时扩展ROM和RAM P 2. 7 P 2. 6 P 2. 5 P 2. 2 … P 2. 0 ALE P 0. 0 -P 0. 7 8031 /WR /PSEN/RD 2: 4 /Y 0 /G译 /Y 1 A 码 /Y 2 B 器 /Y 3 G 74 LS 373 A 0 -A 12 /CE 3#6264 /WE /OE D 7 -D 0 A 0 -A 12 /CE 2#6264 /WE /OE D 7 -D 0 A 0 -A 12 /CE 1#2764 /OE D 7 -D 0 1#: 0000 H— 1 FFFH,2#: 2000 H— 3 FFFH,3#: 4000 H— 5 FFFH
- Random access array
- Parallel ram
- Pengertian sdram
- Random assignment vs random sampling
- Random assignment vs random selection
- Ram nam me lin hai dekhat sabme ram
- Pengertian random access
- Advantages of random file organization
- Crew pram
- Random access control
- Channel partitioning vs random access
- Difference between ram and cache memory
- The internal ram memory of the 8051 is: *
- Primary memory and secondary memory
- Virtual memory in memory hierarchy consists of
- Rocky slowly got up from the mat
- Logical memory is broken into
- Eidetic memory vs iconic memory
- Long term memory vs short term memory
- Difference between implicit and explicit memory