Microprocessors

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• Microprocessors

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Books

• Microcontroller 8051Publisher BaghaniPub.Date 
  1380ISBN 964-7343-00-0Pages 380Author Mohamm
  ad ali Mazidi Jonis Glispi Mazidi
• Translator Dr. Sepidnam

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Books

• The 8051 MicrocontrollerPublisher BaghaniPub.Da
  te 1380Publishing Turn 5Edition Turn 3ISBN 
  964-91532-2-5Pages 383Author Iscott Makenzi
• Translator Rezaei Nia ,Darbandi Azar

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Intruduction

• Microprocessor (MP)(MPU)
• A MP is a CPU on a single chip.
• Components of CPU
• ALU, instruction decoder, registers, bus control
  circuit, etc.
• Micro-computer (M-Computer)
• small computer
• MP peripheral I/O memory specifically for
  data acquisition and control applications
• Microcontroller (MC)
• M-Computer on a single chip of silicon

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MP vs. MC

• architecture
• A MP
• only is a single-chip CPU
• bus is available
• RAM capacity, num of port is seletable
• RAM is larger than ROM (usually)
• A MC
• contains a CPU and RAM,ROM ,timers, Prepherals,
  I/O port in a single IC
• internal hardware is fixed
• Communicate by port
• ROM is larger than RAM (usually)
• Small power consumption
• Single chip, small board
• Implementation is easy
• Low cost

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MP vs. MC cont.

• Applications
• MCs are suitable to control of I/O devices in
  designs requiring a minimum component
• MPs are suitable to processing information in
  computer systems.

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MP vs. MC cont.

• Instruction
• MP have powerfull addressing mode
• MP instruction work with nibble,byte,word,dw
• MC have instruction to work with bits (only I/O)
• MC have slower speed in processing of data

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MP vs. MC cont.

• MC is easy to use and design.
• Only single chip can be a complete system
• interfacing to other devices,
• for example, motors, displays, sensors, and
  communicate with PC.
• In contrast, similar system that builds from
• MP would require a lot of additional units,
• such as RAM, UART, I/O , TIMER and etc.

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MC is a Reusable Hardware

• Logic circuit provides limited function for one
• single design. In order to change circuits
• functionality, we need to redesign the
  circuits.
• MC can reprogram and change functionality of
• every port, input to output or digital to
  analog
• on the fly.

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MC Application

• In cars
• In home (refrigerator )
• In automation of factory
• In shop ( pos )
• In town ( led board , lamps)
• In

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Bus

• a group of wire between two part of hardware
• There are three main bus groups
• ADDRESS BUS
• DATA BUS
• CONTROL BUS
• 2/3 of compter times is used for data transfer
  therefor the data bus bandwidth is very
  important.

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Data Bus

• The Data Bus carries the data which is
  transferred throughout the system. (
  bi-directional)
• Examples of data transfers
• Program instructions being read from memory into
  MPU.
• Data being sent from MPU to I/O port
• Data being read from I/O port going to MPU
• Results from MPU sent to Memory
• These are called read and write operations

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Address Bus

• An address is a binary number that identifies a
  specific memory storage location or I/O port
  involved in a data transfer
• The Address Bus is used to transmit the address
  of the location to the memory or the I/O port.
• The Address Bus is unidirectional ( one way )
  addresses are always issued by the MPU.

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Control Bus

• The Control Bus is another group of signals
  whose functions are to provide synchronization (
  timing control ) between the MPU and the other
  system components.
• Control signals are unidirectional, and are
  mainly outputs from the MPU.
• Example Control signals
• RD read signal asserted to read data into MPU
• WR write signal asserted to write data from MPU

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Main memory

• The duties of the memory are
• To store programs
• To provide data to the MPU on request
• To accept result from the MPU for storage
• Main memory Types
• ROM read only memory. Contains program
  (Firmware). does not lose its contents when power
  is removed (Non-volatile)
• RAM random access memory (read/write memory)
  used as variable data, loses contents when power
  is removed volatile. When power up will contain
  random data values

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Read-Only Memory

• MP can read instructions from ROM quickly
• Cannot write new data to the ROM
• ROM remembers the data, even after power cycled
• Typically, when the power is turned on, the
  microprocessor will start fetching instructions
  from the still-remembered program in ROM
  (bootstrap )

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RAM (Random Access Memory)

• The MP can read the data from RAM quickly,
• The MP can write new data quickly to RAM
• RAM forgets its data if power is turned off
• Two type of is available
• Static RAM(SRAM) ff base, fast, expensive, low
  cap/vol, applied for cache , no refresh
• Dynamic RAM (DRAM) cap base, slow , low cost
  high capacity/volume , applied for main
  memory(pc) need refresh.