by Dr. K.K.Thyagharajan, M.E., Ph.D. Professor Department of Information Technology

1. Microprocessors and Microcontrollers by Dr. K.K.Thyagharajan, M.E., Ph.D. Professor Department of Information Technology R.M.K. Engineering College Websites: www.tansitresearch.com www.geocities.com/kkthyagharajan/ Email: kktflashtraining@yahoo.co.in

2. In the recent years microprocessors have made enormous impact on our day-to-day life. Microprocessors are used in Calculators, Microwave ovens, Television sets, Fridges, Numerical controlled lathes and Washing machines. Microprocessor is the heart of personal computers and also plays supporting roles with in larger computers as smart controllers for graphic displays, storage devices, keyboards and high-speed printers. In most of the automatic control systems microprocessors are used. They are also used in intelligent instruments like Logic analyzers, Storage Oscilloscopes, Frequency Synthesizers, Function Generators, Frequency Meters and Spectrum Analyzers. Here intelligent instruments have new features like programmability are incorporated, which cannot be easily provided in its hard-wired counter part. In industries microprocessors are used in process control i.e. they are used to control process parameters such as speed, temperature and pressure automatically. They are also used in Medical instrumentation like patient monitoring and Data Acquisition Systems. In a distributed Data Acquisition system, microprocessors get data from transducer placed at different locations in the industry and automatically control the various process parameters. Microprocessors are also used in Telecommunications, computer networks, Digital Telephone sets, Routers and Modems that are used in Internet. Introduction Are Microprocessors Needed?

3. Microprocessor is a semiconductor IC (Integrated Circuit) that contains the entire central processing unit of a computer in a single chip. It is spelled with the Greek μ symbol for micro or denoted with the letter u as an alternate (μp or up). A microprocessor is identified with a number and the name of the company that released the microprocessor. For example, Intel 8086 indicates that Intel Corporation has released the processor 8086. Program instructions are fed into the microprocessor in binary form and executed. Generally Microprocessor can be defined as a Multipurpose, Programmable Integrated Circuit with computing and decision making capability (e.g. Intel 8085, 8086, Motorola 6800, Zilog 80). Each processor has a set of Instructions. The computing and decision making capability depends on this Instruction Set. Introduction Contd … What is a microprocessor?

4. When Memory (EPROM and RAM) and I/O (Input/Output) ports are connected with microprocessor it becomes a Microcomputer. Input ports help the microprocessor to receive data from input devices. Output ports help the microprocessor to send data to the output devices. If the microprocessor, memory and I/O ports all are assembled in a single PCB (Printed Circuit Board) then it is called Single-Board Micro Computer. If all these ICs are made in a single chip (VLSI) chip then it is called Single Chip Micro Computer or Micro Controller (e.g. Intel 8031, 8051, 8048). Since the microcontroller and its support circuits are often built into, or embedded in the devices they control, it is also known as Embedded Controller. The instruction set of Micro Controllers has additional instructions to handle I/O ports directly and efficiently. Introduction Contd … What is a Micro Controller ?

5. In microcontrollers, the control program is stored in the on-chip ROM or EPROM. Hence, these programs have high degree of firmness like hardware. These microcontrollers are designed for a single specific purpose and hence called the “firmware”. Microcontrollers have also been developed for Digital Signal Processing, which requires lot of multiplications and additions to be performed with in a short period of time. Digital Signal Processors (DSP) are used where precision processing of analog signals could not be accomplished effectively using conventional analog circuits. Based on the complexity in the instruction set, the microprocessors are classified as Complex Instruction Set computer (CISC) or Reduced Instruction Set Computer (RISC). The CISC processors are general-purpose processors, they have more instructions and they are slower. The RISC processors have reduced number of instructions with higher speed of operations and suitable for specific applications. Another category of processors is Bit Slice Processors, which allow building a custom CPU, and Instruction Set. Introduction Contd … Other Types of Processors

6. A microprocessor-based system reduces the cost, size and development time. It is flexible in operation and simplifies the design procedures. General purpose Microprocessors can be classified as 4-bit, 8-bit, 16-bit, 32-bit and 64-bit processors based on the size of the internal data bus, width of the data the ALU handles at a time, the data width of the internal registers and the size of the data that can be handled by the program instructions. Introduction Contd …

7. Table: Evolution of Microprocessors Texas Instruments, Intel and a Scottish electronic company created the first microprocessors and there is always a debate over who was really created the microprocessor first.

8. Dedicated microcontrollers are used in automatic control systems provided in Microwave Ovens, Washing machines, Sewing machines, digital cameras, video recorders, CD players and ovens. They are also used to regulate gasoline consumption and antilock brakes in automobiles; to monitor alarm systems and to operate automatic tracking and targeting systems in aircrafts, tanks and missiles. Every car manufactured today includes at least one microcontroller for engine control and often more to control additional systems in the car. Since the microcontroller and its support circuits are often built into, or embedded in the devices they control, it is also known as Embedded Controller. The instruction set of Micro Controllers has additional instructions to handle I/O ports directly and efficiently. Where is Microcontroller Used?

9. In addition to Intel, many manufacturers are successfully marketing their microcontrollers; Motorola, Microchip and Atmel are specific among them. The microcontroller explosion was fueled greatly by automotive market place. This is what makes Motorola the number one supplier of 8-bit microcontrollers today. General Instruments developed a series of programmable, high output current, I/O controllers. They called them Peripheral Interface Controllers or PICs. They execute an instruction in one clock cycle at 20 MHz clock frequency. They have 20mA of source and sink current capability on each I/O pin, while typical microcontrollers of that time had only 1mA source and 1.6mA sink currents. General Instruments sold the operations of the semiconductor division along with the factory in Chandler, Arizona to the venture capitalists. This group formed what is known as Microchip Technology. Microchip has grown to become the second largest producer of 8-bit microcontroller. Introduction Contd … Evolution of Microcontrollers

10. Table: Evolution of Microcontrollers The PIC microcontroller was developed in 1990 by Arizona Microchip to meet a demand for a cheap small and practical microcontroller which was both easy to use and program.

11. Any microprocessor or microcontroller based system requires memory to store program and data. There are two types of memory: main memory and secondary memory. Main memory devices are ICs (Integrated Circuits). The main memories are semiconductor devices and they are faster than magnetic devices (floppy disks, magnetic tapes and hard disks ) used as secondary memory devices. The microprocessor can have direct access only to the main memory using the address lines while executing the program because they have processor compatible access time for read and write operations. Therefore, any program stored in the secondary storage devices must be loaded into main memory before they are executed. Memories

12. Figure 1.1: Classification of Memory Devices

13. SRAM (Static Random Access Memory) DRAM (Dynamic Random Access Memory) Mask ROM (Mask Read Only Memory) The non-rewritable ROM is called MASK ROM. The data in these devices are written permanently by masking and metallization with specialized manufacturing process. Mask ROM does not allow the user to write data. OTPROM (One Time Programmable Read Only Memory) EPROM (Erasable Programmable Read Only Memeory) EEPROM (Electrically Erasable Programmable ROM) FRAM (Ferro Electric RAM) This is a nonvolatile memory. It uses a Ferro electric film as the dielectric of a capacitor to store data. Ferro electric films electrically polarize and reverse the polarity, depending on the direction in which the electric field is applied. Classification of Memory Devices Contd …

14. Memory Devices – Symbolic Representations

15. Octal Latches

16. Decoders and Buffers 3 to 8 Decoder Bidirectional Buffer Tri-state Buffer