Microprocessor and Microcontrollers (CSE-3511) Lecture-Segment-5

1. Microprocessor and Microcontrollers (CSE-3511)Lecture-Segment-5 Instructor: SazidZaman Khan Lecturer, Department of Computer Science and Engineering, IIUC

2. Intel 80186 • Intel 80186 microprocessor, sometimes called i186, is an enhanced version of Intel 8086 16-bit processor. Being completely object code compatible with the 8086, the 80186 integrated many system components into one chip, added 7 new instructions. • With the exception of integrated components, the Intel 80186 microprocessor is not very different from the 8086, and, because of this, the 80186 may be considered as an embedded version of 8086. • Had a clock speed of 6 MHz.

3. Intel 80286 • The Intel 80286 also called the iAPX 286, "two-eighty-six"), introduced in 1982, was a 16 bit  microprocessor with 134,000 transistors. Like its contemporary simpler cousin, the 80186, it could correctly execute most software written for the earlier microprocessors. • After the 6 and 8 MHz initial releases, it was subsequently scaled up to 12.5 MHz. • 16-bit microprocessor.

4. Intel 80386 • The third x86 generation of x86 microprocessors, Intel 80386 (i386) was a 32-bit microprocessor backwards compatible with previous generations of 80x86 CPUs. Major new feature in the i386 CPU was 80386 protected mode - this mode fixed many shortcomings that existed in the 80286 processor and in the 80286 protected mode operation. • The Intel 80386 was produced at speeds up to 33 MHz.

5. Intel 80486 • Max CPU clock rate of 16  MHz to 100 MHz. • It’s a 32 bit microprocessor. • Execution time of instructions was significantly reduced. Many load, store and arithmetic instructions executed in just one cycle (assuming that the data was already in the cache).

6. Pentium microprocessors • Pentium, Family of microprocessors developed by Intel corporation. Introduced in 1993 as the successor to Intel’s 80486 microprocessor, the Pentium contained two processors on a single chip and about 3.3 million transistors Using a CISC (complex instruction set computer) architecture, its main features were a 32-bit address bus, a 64-bit data bus, built-in floating-point and memory-management units, and two 8KB caches. It was available with processor speeds ranging from 60 megahertz (MHz) to 200 MHz. The Pentium quickly became the processor of choice for personal computers. It was superseded by ever faster and more powerful processors, the Pentium Pro (1995), the Pentium II (1997), the Pentium III (1999), and the Pentium 4 (2000).

7. Multi tasking • In computing, multitasking is a method by which multiple tasks, also known as processes, share common processing resources such as a CPU. In the case of a computer with a single CPU, only one task is said to be running at any point in time, meaning that the CPU is actively executing instructions for that task. Multitasking solves the problem by Scheduling which task may be the one running at any given time, and when another waiting task gets a turn. The act of reassigning a CPU from one task to another one is called a Context Switch. When context switches occur frequently enough the illusion of parallelism is achieved. Even on computers with more than one CPU (called multiprocessor machines), multitasking allows many more tasks to be run than there are CPUs.

8. Multi-user systems • Multi-user is a term that defines an Operating System or application that allows access by multiple users of a computer. Time-sharing systems are multi-user systems. • Example: A Unix server where multiple users have access.

9. Processes and Threads • In computing, a process is an instance of a computer program that is being executed. It contains the program code and its current activity. Depending on the Operating System (OS), a process may be made up of multiple threads of execution that execute instructions concurrently. • A computer program is a passive collection of instructions; a process is the actual execution of those instructions. Several processes may be associated with the same program; for example, opening up several instances of the same program often means more than one process is being executed.

10. Threads • A thread of execution is the smallest sequence of programmed instructions that can be managed independently by an Operating System scheduler. • On a single processor, multithreading generally occurs by time-division multitasking: the processor switches between different threads. This context switching generally happens frequently enough that the user perceives the threads or tasks as running at the same time. On a multiprocessor or multi-core system, threads can be truly concurrent, with every processor or core executing a separate thread simultaneously.

11. A Process with two threads

12. L1 and L2 Cache • L1 and L2 are levels of cache memory in a computer. If the computer processor can find the data it needs for its next operation in cache memory, it will save time compared to having to get it from random access memory. L1 is "level-1" cache memory, usually built onto the microprocessor chip itself. • L2 (that is, level-2) cache memory is on a separate chip (possibly on an expansion card) that can be accessed more quickly than the larger "main" memory. A popular L2 cache memory size is 1,024 kilobytes (one megabyte).

13. Pentium microprocessors • In October of 1992, Intel released the Pentium. The Pentium introduced the new superscalar technology, which allowed the processor to execute two instructions per clock cycle.  In addition, the Pentium doubled the bus width to 64 bits and incorporated a small internal, or L1 cache (8 KB) built into the processor itself.  • A superscalar CPU can execute more than one instruction per clock cycle. Because processing speeds are measured in clock cycles per second (MHz), a superscalar processor will be faster than a scalar processor rated at the same megahertz.

14. Pentium 4 • The Pentium 4 processor was Intel's first all-new architecture design since 1995.  The new architecture, called NetBurst, was able to achieve higher processor speeds using a more complex pipelining method (a technique to increase the number of instructions that can be executed per unit of time) than previous processors.  It was also the first true 64-bit architecture, prompting software giants like Microsoft to produce 64-bit software, such as Windows XP. • 1.3-3.8 GHz.

15. Pentium M/D • Intel decided that the successor to the Pentium 4 would be divided into two models - one for mobile (laptop) PCs, and another for desktop PCs - hence the brand names of M and D respectively. (Previous Pentium models had different versions made for desktop / mobile PCs, but were marketed under the same name - eg, Pentium 4 vs. Mobile Pentium 4)The Pentium M (for mobile PCs) had much lower power consumption and heat output than previous mobile versions, which gave higher performance than the Pentium 4, even at lower clock speeds (2 GHz max).  The Pentium M is largely responsible for the laptop boom that continues to this day. • The Pentium D (for desktop PCs) was Intel's first dual-core processor.  It was essentially two distinct CPUs, each with its own die, and packaged together as a single processor.  This was a true multiprocessing CPU - common automated tasks such as virus checks and software upgrades could proceed in parallel with other tasks without significantly degrading performance. • Speed: 2.8-3.6 GHz. 

16. Core 2 Processessors • Core 2, in which two CPUs are fabricated on a single die (rather than separate dies, as in the Pentium D). The "2" represents version 2 (since the architecture is actually an upgrade to the original version, named Core), and not the number of processors.  The physical number of processors is identified by the word "Duo" or "Quad" following the Core 2 brand.  Therefore, a Pentium Core 2 Duo is a dual-core CPU (a single die containing two CPUs), and a Pentium Core 2 Quad is a quad-core CPU (two separate dies, each containing two CPUs, giving four total CPUs). • Up to 3.9 GHz.

17. Core 2 VS Dual core Processors • A Core 2 Duo on the other hand is also a Dual Core processor but it is manufactured by Intel and is part of the "Core 2" series. The "2" in the "Core 2" only means, that this series is from the second generation. There is, for example, the "Core 2 Quad", wich obviously has 4 cores. • In a nutshell: • Dual Core = general term for all processors with two cores • Core 2 = series of processors manufactured by Intel • Core 2 Duo = Intel processor  with two cores • Core 2 Quad = Intel processor with four cores

18. Some features of Intel Core i3 processor • Uses 4 threads. Yes, it uses hyperthreading technology which is the latest craze due to its improved efficiency over earlier processors that were put on the market. • This processor consists of 2-4 cores, depending on which one you get your hands on. • Uses less heat and energy than earlier processors, which is always a good thing in this day and age.

19. Some features of Intel Core i5 processor • As with the Core i3 processor, this comes with 2-4 cores, the main difference is that it has a higher clock speed than the Core i3. • This is also a heat and energy efficient processor, but it does seem to be better at this particular job than the Core i3 processor. • The number of threads used in this is no different than the Core i3 with 2-4 threads, and it also uses hyperthreading technology for a boost in performance. • The cache of the Core i5 is bigger than the Core i3.

20. Some features of Intel Core i7 processor • This processor comes with 8 threads, definitely enough to get the job done quickly, maybe even at the speed of light if you’re lucky. It also utilizes hyperthreading technology. • Four cores to take advantage of with this particular series. • Just like the other ones in this Intel series of processors, it is more energy efficient and produces less heat.

21. Embedded microprocessor • An Embedded Processor is a microprocessor that is used in an embedded system. These processors are usually smaller, use a surface mount form factor and consume less power. Embedded processors can be divided into two categories: ordinary microprocessors and microcontrollers. Microcontrollers have more peripherals on the chip. In essence, an embedded processor is a CPU chip used in a system which is not a general-purpose workstation, laptop or desktop computer. Embedded processors can be found in portable devices like digital watches, PDAs, digital cameras, GPS units and MP3 players. 

22. Coprocessor • A coprocessor is a special set of circuits in a microprocessor chip that is designed to manipulate numbers or perform some other specialized function more quickly than the basic microprocessor circuits could perform the same task. A coprocessor offloads specialized processing operations, thereby reducing the burden on the basic microprocessor circuitry and allowing it to work at optimum speed.

23. Bit slicing and bit slice microprocessors • Bit slicing is a technique for constructing a processor from modules of smaller bit width. Each of these components processes one bit field or "slice" of an operand. The grouped processing components would then have the capability to process the chosen full word-length of a particular software design. • Bit slice processors usually consist of an ALU (Arithmetic and Logic Unit)  of 1, 2, 4 or 8 bits and control lines. For example, two 4-bit ALUs could be arranged side by side, with control lines between them, to form an 8-bit CPU, with four slices a 16-bit CPU can be built, and it takes 8 four bit slices for a 32-bit word CPU (so the designer can add as many slices as required to manipulate increasingly longer word lengths).

24. Itanium/Merced Microprocessor • Itanium is Intel's first microprocessor that is based on the 64-bit architecture known as IA-64 . Developed under the code name of Merced , Itanium and its underlying architecture are expected to provide a foundation for the next-generation of software for the server and high-end workstation markets.

25. Itanium/Merced Microprocessor • In addition to supporting a 64-bit processor bus and a set of 28 registers, the 64-bit design allows access to a very large memmory (VLM). In addition, the architecture exploits features in Explicitly Parallel Instruction Computing ( EPIC), a joint Intel and Hewlett-Packard development effort. These provide advances in the Parallel handling of computer instructions known as predication and speculation .

26. Itanium/Merced Microprocessor • An additional Itanium feature includes a Level 3 (L3) cache memory , to supplement the current L1 and L2 cache memories found in most of today's microcomputers.