单片机课件(黄英):第5章 单片机并行存储器扩展 双语教学_黄英_《单片机原理及应用》讲义

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2. Multi-Chip Extension · Two EPROMs: 2764(8KB×8),
total space: 16KB×8
· 13 2
→ A0~A12
→ 25×28
→ P2.4~P2.0、
P0.7~P0.0、 P2.7(Chip Selection Line)
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Fig. 6 Multi-Chip Extension of Program Memory
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1. Memory System of Microcontroller
Fig. 3 Memory Space Arrangement of 8051 Memory 14 System
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2. Address Searching Technology of Memory Extension
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2. Working Modes of EPROM 2716
five types:
·Read
·Unselect
·Programming ·Program Verification ·Programming forbidden
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5.2.3 Extension examples of Program Memory
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(1)Adopts: Line-Selection Method
· Four SRAMs: 6116(2KB×8)
total space: 8KB×8
· 11 → A10~A0 2 211
= 23×28
→ P2.2~P2.0
P0.7~P0.0
P2.6~P2.3(4 Lines Selection)
4 types:
·Read
·Write ·Unselect ·Forbidden
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5.3.3 Examples of Extension Data Memory
Contents:
1. Single Chip Expanding
2. Multi-Chip Expanding
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1. Structure of system extension
· Extension objects: ROM, RAM, I/O interface circuit, etc.
Fig. 1 The structure of system extension
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·In order to realize system extension, the first thing is:
·Bi-direction : MCU ←→ Memory, I/O interface
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(2)System Bus Construction
· Address Bus: P0(low 8-bit address lines): needs 8-bit address latch(74LS273, 74LS373) P2(high address lines): don’t need when < 256 bytes(extended memory) · Data Bus: P0 · Control Bus: ALE, PSEN, EA, RD, WR
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Fig. 5 Single Chip Extension of Program Memory
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Address Arrangement: 8000H ~ 87FFH
There are 16 overlap areas(mapping areas): ∵ P2.6~P2.3 = 0000~FFFF, 24 =16
to construct system bus
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2. System Bus & its construction method
(1)System Bus ·System Bus is divided into three groups: AB、DB、CB
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① Address Bus(AB)
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(1) Line-Selection Method ·Uses address line directly. ·Suitable for expanding memory in small scale.
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(2) Encoding Method ·Uses encoder to produce chipselection signal. ① Dual 2-4 encoder: 74LS139 ② 3-8 encoder: 74LS138 ·Suitable for expanding memory in large scale.
Contents:
1. Single Chip Extension 2. Multi-Chip Extension
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1. Single Chip Extension · EPROM: 2716(2KB×8) 211 → A0~A10 → 23×28 → P2.2~P2.0 P0.7~P0.0 P2.7(Chip Selection Line)
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Fig. 9 Multi-Chip Extension of Data Memory
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Address Arrangement: Chip #1: 7000H ~ 77FFH Chip #2: 6800H ~ 6FFFH
Chip #3: 5800H ~ 5FFFH
To solve the followings: (1)Address arrangement of each expanded memory chip. (2)Selection of each expanded memory chip. (The main problem) 2 ways: ·Line-Selection Method ·Encoding Method
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2. Multi-Chip Expanding · Four SRAMs: 6116(2KB×8) total space: 8KB×8 · 11 → A10~A0 2 (1)Adopts: Line-Selection Method (2)Adopts: Encoding Method
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5.2 Program memory extension
Contents:
5.2.1 Read Only Memory(ROM) 5.2.2 Typical extension Chip of Program Memory 5.2.3 Extension examples of Program Memory
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② Data Bus(DB) ·Carry data information · Bi-direction: MCU Memory, I/O interface · number: Word number(8 bits) Bit
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③ Control Bus(CB)
·Carry control information
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5.2.1 Read Only Memory(ROM)
1. Mask ROM 2. PROM/otpROM
· PROM: Programmable ROM · OtpROM: One Time Programmable ROM
3. EPROM
· EPROM: Erasable Programmable ROM · Types: 2716(2KB×8),2732(4KB×8), 2764(8KB×8),27128(16KB×8), 27256(32KB×8), etc.
Contents: 1. Pins of EPROM 2716(2KB×8)
2. Working Modes of EPROM 2716
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1. Pins of EPROM 2716(2KB×8)
· 11 → A0~A10 2
Fig.4 Pins Arrangement of 2716
5.3.3 Examples of extension Data Memory
5.3.4 Features and usage of memory system
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5.3.1 Random-Access Memory(RAM)
1. SRAM(Static RAM) 2. DRAM(Dynamic RAM)
Microcontroller Principle and Application
Chapter 5 : Memory extension
主讲教师:黄英
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Chapter 5
Memory extension
Contents:
5.1 Memory extension introduction 5.2 Program memory extension 5.3 Data memory extension
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5.3.2 Typical Extension Chip of Data Memory
6116(2KB×8): 211 → A10~A0 6264(8KB×8): 213 → A12~A0
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1. Pins Arrangement of SRAM 6116(2KB×8)
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2. Working Modes of SRAM 6116
1. Single Chip Expanding
· 6116(2KB×8) 211 → A10~A0 → 23×28 → P2.2~P2.0 → P0.7~P0.0
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Fig. 8 Single Chip Extension of Data Memory
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Address Arrangement: 0000H ~ 07FFH
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Fig. 2 Construction Diagram of System Bus Extension
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5.1.2 Memory extension & addresses arrangement
Contents: 1. Memory System of Microcontroller 2. Address Searching Technology of Memory Extension
Home work
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5.1 Memory extension introduction
Contents:
5.1.1 System extension & its structure
5.1.2 Memory extension & addresses arrangement
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5.1.1 System extension and it’s structure Contents: 1. Structure of system extension 2. System Bus & its construction method
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Address Arrangement: 29 Chip #1: 0000H ~ 1FFFH, Chip #2: 8000H ~ 9FFFH Return
5.3 Data memory extension
Contents:
5.3.1 Random-Access Memory(RAM)
5.3.2 Typical extension Chip of Data Memory
4. EEPROM(E2PROM)
· 2PROM: Electrically Erasable Programmable E · Types: 28C16,28C17,2817A, etc.
5. Flash ROM
· Types: 28F256, 28F516, etc.
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5.2.2 Typical Extension Chip of Program Memory
· Carry address information.
· Single direction: MCU → Memory, I/O interface · number determines the number of memory Its cells: n → 2n · Maximal extension space: 216 cells = 64KB
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