Microprocessor Systems Design EEE315M2

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Microprocessor Systems Design(EEE315M2)

• Dr. N.H. Siddique,
• Room MG037, Ext. 75340,
• email nh.siddique_at_ulster.ac.uk

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Aims

• The aims of the microprocessor part of this
  module are
• introduce the architecture of a simple
  microprocessor and the fundamentals of
  microprocessor based systems (Lectures)
• utilise assembly language programming to
  illustrate the architecture of a simple processor
  (laboratories)

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Assessment

• This module is assessed using continuous
  assessment methods.
• Class test 1 (in Week 7/8) - marks 30 of CA
• Assignment 1 (in week 11) - marks 30 of CA
• Weekly laboratory (W1-W10) marks 40 of CA

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Reading List

• Recommended Reading
• Huang Han-Way (2001), MC 68HC11 An Introduction,
  Software and Hardware Interfacing, Delmar Thomson
  Learning, ISBN 0-7668-1600-1
• M. Rafiquzzaman.(1995), Microprocessors and
  Microprocessor-based System Design CRC Press,
  ISBN 0-8493-4475-1.

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Computer Hardware Organization
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Registers

• Register is a storage location in the CPU
• Used to hold data/address during execution of an
  instruction
• Registers have faster access time than memory
• Number of registers available for programming
  varies from ?P to ?P

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Arithmetic Logic Unit (ALU)

• ALU does all arithmetic and logical operations
• ALU receives data from registers/memory and
  performs the task
• ALU writes the result back to register/memory

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Control unit

• Contains hardware instruction logic
• Decodes and monitors execution of instructions

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Bus

• Wires through which data and information are
  interchanged between units
• Three types of bus (more later)
• - Address bus - Data bus - Control bus

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Program counter(PC)

• Register within CPU
• Holds the address of the next instruction to be
  fetched from memory
• Goes through step by step counting sequence -
  causes the computer to read successive
  instruction stored in memory
• PC is modified with new address when there is a
  jump or transfer or subroutine call instruction
• example

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Program counter (PC)
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Status register

• After an ALU operation following can occur
• -carry/borrow for addition/subtraction
• -overflow
• -result zero, negative or positive
• Register which contains flags to indicate these
  status of any processor operation
• Programmer can use these status condition for
  program control
• example

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Flags

• Carry flag
• 0 0 1 1 0 1 0 1
• 0 1 0 0 0 0 1 1
• 0 0 1 1 1 1 0 0 0
• 1 0 0 0 0 0 1 0
• 1 0 1 0 0 0 1 1
• 1 0 0 1 0 0 1 0 1

Carry 0
Carry 1
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Index register

• Almost all ?Ps have an index register
• Holds a base address to be added to an offset
• Base address and the offset forms the effective
  address
• example

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Index register
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Stack pointer (SP)

• An area of RAM used for temporary storage of
  data/return address is called stack
• SP is a register within CPU that points to the
  next free location on the stack
• Each time a byte is put onto stack, SP is
  decremented
• Each time a byte is retrieved from stack, SP is
  incremented
• example

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Stack pointer
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Stack pointer
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Stack pointer
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Instruction set

• To program a ?P, a variety of data manipulation,
  arithmetic and logical instructions are featured
  for a processor
• Instructions can be organised into functional
  groups
• -Data movement -Arithmetic
• -Logical -Bit manipulation
• -Shift/rotate -Branch/Jump
• -Subroutine call -Interrupt handling
• -Miscellaneous
• More detail later (for a specific processor)

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Addressing modes

• To perform an operation, operands are to be
  supplied
• Operands can come from registers, memory
  locations or directly as part of an instruction
• Addressing mode says from where the operands
  come from
• Very common addressing modes are
• -Immediate, direct, inherent, relative,
  indexed (more detail later)

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Memory

• Random Access Memory (RAM)
• SRAM static RAM uses bipolar transistors (4-6)
  and very fast but expensive
• DRAM dynamic RAM uses one transistor and one
  capacitor information stored in capacitor
  periodic refresh operation required

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Memory

• Read Only Memory (ROM)
• Mask-programmed read-only memory (MROM)
  programmed when being manufactured
• Programmable read-only memory (PROM) the memory
  chip can be programmed by the end user
• EPROM programmable memory that can be erased
• EEPROM programmable memory that can be erased by
  electrical signals and reprogrammed

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Program

• A program is sequence of instructions
• A program can be written in
• Low level language e.g. assembly language
• High level language e.g. C, PASCAL
• Assembly language program is converted to machine
  code by an assembler
• High level language is translated into machine
  code by a compiler

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Application of Microprocessor
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(No Transcript)
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HC11 Data transfer instruction

• Data transfer from memory to register
• LDAA ltoprgt A ? M
• LDAB ltoprgt B ? M
• LDD ltoprgt D ? M M1
• LDX ltoprgt IXH ? M , IXL ? M1
• LDY ltoprgt
• LDS ltoprgt SPH ? M , SPL ? M1
• ltoprgt can be immediate, direct, extended, or
  index mode
• Examples
• LDAA 10
• LDX 1000

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Data transfers from register to memory

• STAA ltMgt Transfer contents of A to M M ? A
• STAB ltMgt Transfer contents of B to M M ? B
• STD ltMgt Transfer contents of D to M MM1 ?
  D

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Data transfers from register to register

• TBA Transfer contents of B to A A ? B
• TAB Transfer contents of A to B B ? A
• TAP Transfer contents of A to CCR CCR ? A
• TPA Transfer contents of CCR to A A ? CCR

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Example Program

• Exercise 1 Load data into register and store it
  onto memory location
• .area text
• _main
• LDAA 06 Loads accumulator A with hex value
  6
• This is written as A? 06
• STAA 2025 Stores the content of accumulator
  A on to memory location 2025, 2025 ? A
• LDAB 2025 Loads accumulator B with the
  contents of memory location 2025, B?2025
• STAB 1064 Stores the content of accumulator
  B on to memory
• location 1064, 1064 ? B
• SWI Returns to monitor

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Example Program

• Exercise 2 Data exchange between registers
• .area text
• _main
• LDAB 03 B ? 03
• TBA Transfer contents of B to A A ? B
• STAA 1064 Store contents of A onto location
  1064, 1064 ? A
• SWI

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Example Program

• Exercise 3 Addition of two numbers
• .area text
• _main
• LDAB 02 B ?02
• STAB 2025 2025 ? B
• LDAA 01 A? 01
• ADDA 2025 A?A 2025
• STAA 1064 1064 ? A
• SWI