SYSTEM BUS AND MOCROPROCESSORS HISTORY Dr. M. Hebaishy momara@su.edu.sa http://colleges.su.edu.sa/dawadmi/fos/pages/hebaishy.aspx Digital Logic Design Ch1-1
SYSTEM BUS The CPU sends various data values, instructions and information to all the devices and components inside the computer. If you look at the bottom of a motherboard you'll see a whole network of lines or electronic pathways that join the different components together. This network of wires or electronic pathways is called the 'Bus'. There are three types of system Bus Data Bus Address Bus Control Bus Digital Logic Design Ch1-2
The CPU is connected to memory and I/O devices through a strip of wires called a bus. The bus inside a computer carries information from place to place. In every computer there are three types of busses: 1. Address Bus: The address bus is used to identify the memory location or I/O device the processor intends to communicate with. The width of the Address Bus rages from 20 bits (8086) to 36 bits for (Pentium II). 2. Data Bus: Data bus is used by the CPU to get data from / to send data to the memory or the I/O devices. The width of a microprocessor is used to classify the microprocessor. The size of data bus of Intel microprocessors vary between 8-bit (8085) to 64-bit (Pentium). 3. Control Bus. How can we tell if the address on the bus is memory address or an I/O device address? This where the control bus comes in. Each time the processor outputs an address it also activates one of the four control bus signals: Memory Read, Memory Write, I/O Read and I/O Write. Digital Logic Design Ch1-3
The address and control bus contains output lines only, therefore it is unidirectional, but the data bus is bidirectional. There two types of memory used in microcomputers: RAM (Random Access Memory/ Read-Write memory) is used by the computer for the temporary storage of the programs that is running. Data is lost when the computer is turned off. So known as volatile memory. ROM (Read Only Memory) the information in ROM is permanent and not lost when the power is turned off. Therefore, it is called nonvolatile memory. Note that RAM is sometimes referred as primary storage, where magnetic /optical disks are called secondary storage. Digital Logic Design Ch1-4
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Bottom of Motherboard System Bus Digital Logic Design Ch1-6
Inside the CPU: A program stored in the memory provides instructions to the CPU to perform a specific action. This action can be a simple addition. It is function of the CPU to fetch the program instructions from the memory and execute them. 1. The CPU contains a number of registers to store information inside the CPU temporarily. Registers inside the CPU can be 8-bit, 16-bit, 32-bit or even 64-bit depending on the CPU. 2. The CPU also contains Arithmetic and Logic Unit (ALU). The ALU performs arithmetic (add, subtract, multiply, divide) and logic (AND, OR, NOT) functions. 3. The CPU contains a program counter also known as the Instruction Pointer to point the address of the next instruction to be executed. 4. Instruction Decoder is a kind of dictionary which is used to interpret the meaning of the instruction fetched into the CPU. Appropriate control signals are generated according to the meaning of the instruction. Digital Logic Design Ch1-7
Internal block diagram of a CPU Digital Logic Design Ch1-8
The Figure below demonstrates the interaction between the CPU, memory and I/O Devices. Digital Logic Design Ch1-9
Types of System Buses Data Bus Address Bus Control Bus Digital Logic Design Ch1-10
Data Bus A collection of wires through which data is transmitted from one part of a computer to another is called Data Bus. Data Bus can be thought of as a highway on which data travels within a computer. This bus connects all the computer components to the CPU and main memory. The size (width) of bus determines how much data can be transmitted at one time. E.g.: A 16-bit bus can transmit 16 bits of data at a time. 32-bit bus can transmit 32 bits at a time. Digital Logic Design Ch1-11
Address Bus A collection of wires used to identify particular location in main memory is called Address Bus. Or in other words, the information used to describe the memory locations travels along the address bus. The size of address bus determines how many unique memory locations can be addressed. E.g.: A system with 4-bit address bus can address 2^4 = 16 Bytes of memory. A system with 16-bit address bus can address 2^16 = 64 KB of memory. A system with 20-bit address bus can address 2^20 = 1 MB of memory. Digital Logic Design Ch1-12
Control Bus The connections that carry control information between the CPU and other devices within the computer is called Control Bus. The control bus carries signals that report the status of various devices. E.g.: This bus is used to indicate whether the CPU is reading from memory or writing to memory. Digital Logic Design Ch1-13
HISTORY OF MICROPROCESSORS Digital Logic Design Ch1-14
Contents Introduction 4-Bit Microprocessors 8-Bit Microprocessors 16-Bit Microprocessors 32-Bit Microprocessors 64-Bit Microprocessors Digital Logic Design Ch1-15
Introduction Fairchild Semiconductors (founded in 1957) invented the first IC in 1959. In 1968, Robert Noyce, Gordan Moore, Andrew Grove resigned from Fairchild Semiconductors. They founded their own company Intel (Integrated Electronics). Intel grown from 3 man start-up in 1968 to industrial giant by 1981. It had 20,000 employees and $188 million Digital Logic Design Ch1-16
4-bit Microprocessors Intel 4004 Introduced in 1971. It was the first microprocessor by Intel. It was a 4-bit µp. Its clock speed was 740KHz. It had 2,300 transistors. It could execute around 60,000 instructions per second. Digital Logic Design Ch1-17
Intel 4040 Introduced in 1974. It was also 4-bit µp. Digital Logic Design Ch1-18
8-bit Microprocessors Intel 8008 Introduced in 1972. It was first 8-bit µp. Its clock speed was 500 KHz. Could execute 50,000 instructions per second. Digital Logic Design Ch1-19
Intel 8080 Introduced in 1974. It was also 8-bit µp. Its clock speed was 2 MHz. It had 6,000 transistors. Was 10 times faster than 8008. Could execute 5,00,000 instructions per second. Digital Logic Design Ch1-20
Intel 8085 Introduced in 1976. It was also 8-bit µp. Its clock speed was 3 MHz. Its data bus is 8-bit and address bus is 16-bit. It had 6,500 transistors. Could execute 7,69,230 instructions per second. It could access 64 KB of memory. It had 246 instructions. Over 100 million copies were sold. Digital Logic Design Ch1-21
16-bit Microprocessors Intel 8086 Introduced in 1978. It was first 16-bit µp. Its clock speed is 4.77 MHz, 8 MHz and 10 MHz, depending on the version. Its data bus is 16-bit and address bus is 20-bit. It had 29,000 transistors. Could execute 2.5 million instructions per second. It could access 1 MB of memory. It had 22,000 instructions. It had Multiply and Divide instructions. Digital Logic Design Ch1-22
Intel 8088 Introduced in 1979. It was also 16-bit µp. It was created as a cheaper version of Intel s 8086. It was a 16-bit processor with an 8-bit external bus. Could execute 2.5 million instructions per second. This chip became the most popular in the computer industry when IBM used it for its first PC. Digital Logic Design Ch1-23
Intel 80186 & 80188 Introduced in 1982. They were 16-bit µps. Clock speed was 6 MHz. 80188 was a cheaper version of 80186 with an 8-bit external data bus. They had additional components like: Interrupt Controller Clock Generator Local Bus Controller Counters Digital Logic Design Ch1-24
Intel 80286 Introduced in 1982. It was 16-bit µp. Its clock speed was 8 MHz. Its data bus is 16-bit and address bus is 24-bit. It could address 16 MB of memory. It had 1,34,000 transistors. It could execute 4 million instructions per second. Digital Logic Design Ch1-25
32-bit Microprocessors Intel 80386 Introduced in 1986. It was first 32-bit µp. Its data bus is 32-bit and address bus is 32-bit. It could address 4 GB of memory. It had 2,75,000 transistors. Its clock speed varied from 16 MHz to 33 MHz depending upon the various versions. Different versions: 80386 DX 80386 SX 80386 SL Intel 80386 became the best selling microprocessor in history. Digital Logic Design Ch1-26
Intel 80486 Introduced in 1989. It was also 32-bit µp. It had 1.2 million transistors. Its clock speed varied from 16 MHz to 100 MHz depending upon the various versions. It had five different versions: 80486 DX 80486 SX 80486 DX2 80486 SL 80486 DX4 8 KB of cache memory was introduced. Digital Logic Design Ch1-27
Intel Pentium Introduced in 1993. It was also 32-bit µp. It was originally named 80586. Its clock speed was 66 MHz. Its data bus is 32-bit and address bus is 32-bit. It could address 4 GB of memory. Could execute 110 million instructions per second. Cache memory: 8 KB for instructions. 8 KB for data. Digital Logic Design Ch1-28
Intel Pentium Pro Introduced in 1995. It was also 32-bit µp. It had L2 cache of 256 KB. It had 21 million transistors. It was primarily used in server systems. Cache memory: 8 KB for instructions. 8 KB for data. It had L2 cache of 256 KB. Digital Logic Design Ch1-29
Intel Pentium II Introduced in 1997. It was also 32-bit µp. Its clock speed was 233 MHz to 500 MHz. Could execute 333 million instructions per second. MMX technology was supported. L2 cache & processor were on one circuit. Digital Logic Design Ch1-30
Intel Pentium II Xeon Introduced in 1998. It was also 32-bit µp. It was designed for servers. Its clock speed was 400 MHz to 450 MHz. L1 cache of 32 KB & L2 cache of 512 KB, 1MB or 2 MB. It could work with 4 Xeons in same system. Digital Logic Design Ch1-31
Intel Pentium III Introduced in 1999. It was also 32-bit µp. Its clock speed varied from 500 MHz to 1.4 GHz. It had 9.5 million transistors. Digital Logic Design Ch1-32
Intel Pentium IV Introduced in 2000. It was also 32-bit µp. Its clock speed was from 1.3 GHz to 3.8 GHz. L1 cache was of 32 KB & L2 cache of 256 KB. It had 42 million transistors. All internal connections were made from aluminium to copper. Digital Logic Design Ch1-33
Intel Dual Core Introduced in 2006. It is 32-bit or 64-bit µp. It has two cores. Both the cores have there own internal bus and L1 cache, but share the external bus and L2 cache (Next Slide). It supported SMT technology. SMT: Simultaneously Multi-Threading E.g.: Adobe Photoshop supported SMT. Digital Logic Design Ch1-34
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64-bit Microprocessors Intel Core 2 Introduced in 2006. It is a 64-bit µp. Its clock speed is from 1.2 GHz to 3 GHz. It has 291 million transistors. It has 64 KB of L1 cache per core and 4 MB of L2 cache. It is launched in three different versions: Intel Core 2 Duo Intel Core 2 Quad Intel Core 2 Extreme Digital Logic Design Ch1-36
Intel Core i7 Introduced in 2008. It is a 64-bit µp. It has 4 physical cores. Its clock speed is from 2.66 GHz to 3.33 GHz. It has 781 million transistors. It has 64 KB of L1 cache per core, 256 KB of L2 cache and 8 MB of L3 cache. Digital Logic Design Ch1-37
Intel Core i5 Introduced in 2009. It is a 64-bit µp. It has 4 physical cores. Its clock speed is from 2.40 GHz to 3.60 GHz. It has 781 million transistors. It has 64 KB of L1 cache per core, 256 KB of L2 cache and 8 MB of L3 cache. Digital Logic Design Ch1-38
Intel Core i3 Introduced in 2010. It is a 64-bit µp. It has 2 physical cores. Its clock speed is from 2.93 GHz to 3.33 GHz. It has 781 million transistors. It has 64 KB of L1 cache per core, 512 KB of L2 cache and 4 MB of L3 cache. Digital Logic Design Ch1-39
Brief History of the Computers 1946 The first generation of Computer ENIAC was started to be used based on the vacuum tube technology. 1958 the first transistorized computer TRADIC was announced by IBM. 1959 first IC was invented. 1960s ICs were started to be used in CPU boards. 1970s entire CPU was put in a single chip. (1971 the first microprocessor of Intel 4004 (4-bit data bus and 2300 transistors) Late 1970s Intel 8080/85 appeared with 8-bit data bus and 16-bit address bus and used from traffic light controllers to homemade computers. 1981 First PC was introduced by IBM with Intel 8088 microprocessor. Motorolla emerged with 6800. Apple Machintosh computers started to use 68000 series of Digital Logic Design Ch1-40
EVOLUTION OF INTEL 80X86 FAMILY MICROPROCESSORS Digital Logic Design Ch1-41
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Quiz Digital Logic Design Ch1-43