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Basics of micro controllers for biginners
- 3. MICROPROCESSOR Microprocessor • Is a programmable digital component that in cooperates the function of CPU on a single semiconducting integrated circuit. • Is the integration of number of useful function into a single IC package that has; -Ability to execute a stored set of instruction to carry out user defined task. - Ability to access the external memory chips to both read and write data to and from the memory
- 5. Basic architecture • Von neumann Architecture. • Harvard architecture
- 6. Von Neumann Architecture. • The design has a single memory bank for storing both program and data. • It has single bus which is multiplexed to be used as both address bus and data bus. • The content of RAM can be used for both variable storage as well as program storage.
- 7. Harvard Architecture • Separate memory banks for program and data storage. • It has RAM for data storage and separate ROM for storing program • It has two separate address bus for -Program memory - Data memory
- 8. Comparison Von Neumann Versus Harvard Von Neumann Harvard • Single memory for both program and data • Separate memory for program and data • Single bus used to access both data and memory • Separate buses available to access program and data • Instruction parallelism is not possible • Instruction parallelism can be done • It takes more than one machine cycle (Fetching and execution are done) • It takes only one machine cycle. Fetching and execution are done simultaneous
- 9. Advantages of Von Neumann Architecture • It simplifies the microcontroller chip design because only one memory is accessed. • The content of RAM can be used for both variable (data) as well as program (instruction) storage
- 10. Advantages of Harvard Architecture • The Harvard architecture tends to execute instruction in fewer instruction cycle than Von Neumann architecture. This is because greater amount of parallelism is possible.
- 11. Instruction Set • CISC- Complex Instruction Set Computer • RISC- Reduced Instruction Set Computer
- 12. Complex Instruction Set Computer • Is Microprocessor that understand large number of complex instruction but it process them relatively slowly • Internal instruction involves many individual execution steps and thus many clock cycles. • The design is complex, costly and also instruction set consist of more than 100 instruction
- 13. Reduced Instruction Set Computer • Is Microprocessor that uses relatively simple architecture with fewer built in command. • Increase in speed. • Design is relatively simpler, economical and usually has less than 100 instructions
- 14. Comparison RISC versus RISC RISC CISC • Less number of Instruction • More number of Instruction • All are single cycle instruction • Each instruction take at least 2 or 3 machine cycle. • Design of architecture is easier and cheap • Design of architecture is complex and costly • Program length get increased due to shortage of instructions • Program length is less because variety of instructions is available • Execution speed is faster since most instruction are single cycled • Execution speed is low since the instruction takes many machine cycles • Example; PIC series, ARM processors • Examples; 8051 families, Pentium
- 15. MICROCONTROLLERS Is a small (micro) single chip computer designed to perform a specific function, and the specific function is to control objects, process or events. It is dedicated to one task or set of closely related task. It is similar to PC(it has similar components but onto a single chip) -CPU, memory (ROM and RAM). -I/O ports, serial ports. - Timers e.t.c
- 17. Comparison Microprocessor Versus Microcontroller Microprocessor Microcontroller • Memoryhastobeinterfacedexternally • Hasinbuiltprogramanddatamemory • I/Oportshastobeinterfaced • HasInbuiltdigital/analogueI/Oports • HasnointernalTimers,serialportsetc • HasTimer,serialportsandotherfeatures • Highclockrates >3GHz • Slowclockrates(4–20MHz) • Buswidthverywide • Buswidthverynarrow • Expensive • Lessexpensive
- 18. In Summary Microprocessor Is a general purpose chip and is used in multifunction computer or device with the help of multiple chips to handle various tasks Microcontroller Is a self contained, CPU, RAM, ROM, I/O ports and Timers on the same chip function independently as a single chip computer dedicated to specific task to control single system
- 19. Why Microcontroller? • Task specific. • Add computer power to the device to enable it to perform more better at low cost. • Low cost, small packaging, low power requirements. • Ideal for application in which low cost, power and space is crucial. • Easy integration with other circuits • Programmable and re-programmable.
- 20. Embedded System • The system to control, monitor or assist the operation of equipment, machinery or plant. The term “Embedded” reflect the fact that they are integral part of the system they control.
- 21. Common characteristics of Embedded Systems • Specific and single functioned Execute a single instruction repeatedly • Optimized for hardware Compact, low cost, fast, low power. • Reactive and operated in real time
- 23. MICROCONTROLLER BASED PROJECTS HOW TO SELECT A SUITABLE MICROCONTROLLER FOR THE PROJECT
- 24. Step 1: Make a list of required hardware interfaces
- 25. Step 2: Examine the software architecture • How heavy or how light the processing requirements will determine whether you go with an 80 MHz DSP or an 8 MHz 8051 • Are there any high frequency control loops or sensors? • Estimate how long and how often each task will need to run • How much processing power will be needed. • The amount of computing power required will be one of the biggest requirements for the architecture and frequency of the microcontroller.(how fast a machine can perform an operation).
- 26. Step 3: Select the architecture • Can the application get by with eight bit architectures? How about 16 bits? Does it require a 32 bit ARM core? • Microcontroller selection can be an iterative process. You may select a 16-bit part in this step but then in a later step find that a 32 bit ARM part works better.
- 27. Step 4: Identify Memory Needs • Flash and RAM are two very critical components of any microcontrollers. Making sure that you don’t run out of program space or variable space is undoubtedly of highest priority.
- 28. Step 5: Start searching for microcontrollers • One place that can be a good place to start is with a microcontroller supplier
- 29. Step 6: Examine Costs and Power Constraints • Examine the power requirements and cost of the part. If the device will be powered from a battery and mobile, then making sure the parts are low-power If it doesn’t meet power requirements then keep weeding the list down until you have a select few.
- 30. Step 7: Check part availability • Starts checking on how available the part is. • What are your requirements for availability?
- 31. Step 8: Select a development kit • One of the best parts of selecting a new microcontroller is finding a development kit to play with and learn the inner working of the controller.
- 32. Step 9: Investigate compilers and tools • Examine the compiler and tools that are available. It is important to make sure that all the necessary tools are available for the part. Without the right tools the development process could become tedious and expensive.
- 33. Step 10: Start Experimenting
- 34. Programming Language The preferred programming language is C language.
- 35. Why C language is preferable language
- 36. Software Architecture Software architecture that will be used is Super loop Architecture.
- 37. Super loop • A super loop is a program structure comprised of an infinite loop, with all the tasks of the system contained in that loop. • General pseudo-code for a super-loop implementation is given as: Function Main_Function() { Initialization(); Do_Forever { Check_Status(); Do_Calculations(); Output_Response(); } }
- 38. Why Super-loop is needed • We have no operating system to return to, so the application will keep looping until the system power is removed. • It help to perform all the tasks of the system in a reasonable amount of time • It help task to be performed in good order.
- 39. Strength of Super loop
- 40. Weakness of Super loop
- 41. Compiler • A compiler is a computer program (or set of programs) that transforms source code written in a programming language (the source language) into another computer language (the target language, often having a binary form known as object code). • The preferred compiler is Mikro C compiler
- 42. Why Mikro C is the preferred compiler? • lots of hardware and software libraries. • Compiler comes with comprehensive Help file and lots of ready-to-use examples designed to get you started in no time.
- 43. Characteristics • RISC CPUs – 8-bit – 16-bit • Number of I/O pins: 4-70 • Memory types and sizes: – Flash; OTP; ROM – 0.5k – 256k
- 44. Speeds • All PICs require oscillators to execute instructions: – Internal* (low speeds, up to 8 MHz) – External (high speeds, up to 40 MHz) • Instructions are executed at least at ¼ oscillator speed (4 clocks/instruction) (* Note: not all PICs have internal oscillators)
- 45. A/D converters and C/C modules • All PICs have between 0 and 16 A/D converters with 8/10-bit resolution • 8-16 bit Timers/Counters • Comparator Modules (0-2)
- 46. Example: PIC16F877A 5/6 Programming pins 8 A/D channels 2 Oscillator Inputs 2 RS-232 inputs 33 I/O ports