Microcomputer Architecture

1. Revised 5/28/2012 Slide # 1 Microcomputer Architecture

2. Revised 5/28/2012 Slide # 2 Please fill out the 3x5 card Name Prior math/stats/comp sc coursework Any computer expertise Planned post-grad plans Hopes/fears about this class! Something I should know about you or might find interesting (helps me remember) A Password (make it one you will remember, but not one you also use for anything important. This is for web page access)

3. Revised 5/28/2012 Slide # 3 Computers - Basic Architecture Computers have: Input Output Storage (Memory) Connectivity (can be seen as an IO channel)

4. Revised 5/28/2012 Slide # 4 Using the Computer

5. Revised 5/28/2012 Slide # 5 Some simple binary arithmetic Why Binary? Why Decimal? People count by 10s Because we have ten fingers Computers count by ones Because magnetic storage media can electricity can be easily set to “on” and “off” Or 0 and 1

6. Revised 5/28/2012 Slide # 6 Bits and Bytes All of the data, programs, and circuitry are digital or binary in nature, meaning that they are comprised of the elements 0 and 1. This is somewhat different than standard (not digital or HD) radio, television, and vinyl or LP records, which operate on analog methods. Analog electronics means that devices use an electrical signal that has amplitude or magnitude instead of a stream of 0's and 1's. Why binary? Because the storage of information on magnetic media is accomplished by arranging bits of metallic oxide in one of two alignments, corresponding to 0 or 1. This allows for massive numbers of 0s and 1s to be stored in a very small space. This smallest unit of information (a 0 or a 1) is called a bit. Collections of bits can be organized into larger chunks. 4 bits = 1 nibble 8 bits = 2 nibbles = 1 byte

7. Revised 5/28/2012 Slide # 7 Counting in Base 2 (Binary)

8. Revised 5/28/2012 Slide # 8 Other Bases are useful as well

9. Revised 5/28/2012 Slide # 9 ASCII Characters A single byte, consisting of 8 bits can represent 256 different numbers The largest number represented by n bits is 2n-1 Hence 28-1 = 255 Including 0, that makes 256 different numbers These 256 numbers have been standardized to the ASCII character set. All PCs use the same number to represent the same character. This will expand with Unicode

10. Revised 5/28/2012 Slide # 10 What Do Computers Do? Computers add Computers Subtract Which is negative addition Computers multiply Which is adding multiple times Computers Divide Which is negative adding a bunch of times Computers do more complicated things – Square roots, power functions, exponentiation, logarithms All by numeric approximation – which is addition They move around the data that they add. That’s all…

11. Revised 5/28/2012 Slide # 11 The CPU Functions as the arithmetic unit of the computer It operates according to it’s clock cycle A 1.8 GHz computer has a clock that cycles 1.8 billion times per second

12. Revised 5/28/2012 Slide # 12 Binary addition Adding Binary Numbers is Simple 3 Rules 0 + 0 = 0 1 + 0 = 1 1 + 1 = 10 ( = 0 and carry the 1 to the next higher column)

13. Revised 5/28/2012 Slide # 13 Graphic Representation of Addition

14. Revised 5/28/2012 Slide # 14 Does this look familiar Binary Addition is the electrical/electronic application of the “exclusive or” from logic Many numbers that are encountered frequently in computers arise from binary arithmetic

15. Revised 5/28/2012 Slide # 15 Get on the Bus Computers read data on the “buses” that the CPU has Two Buses of note Data Bus The data read into (or written from) the CPU or memory Address Bus The spot in memory to read from or write to

16. Revised 5/28/2012 Slide # 16 The Power of 2

17. Revised 5/28/2012 Slide # 17 More Powers of 2

18. Revised 5/28/2012 Slide # 18 And Even More Powers of 2

19. Revised 5/28/2012 Slide # 19 Digital Systems So, in the end, we can see that computers simply move ad add 0’s and 1’s. And out of this, we can build incredibly rich and complex experiences Such as Or…

20. Revised 5/28/2012 Slide # 20