1. Where Are We Going? CPSC 120 Principles of Computer Science September 23, 2012

2. Course Themes  Complexity and Structure  Encoding and Decoding  Hardware and Software  Theory and Application  Local and Remote  Humans and Machines

3. Coming Attractions  Basic Electricity Theory  Switches, lights, and LEDs  Logic of switches: AND, OR, NOT, etc  Computing using logic: Adders  Arithmetic/logic units: ALUs  Central processing units: CPUs  Microprocessors: Real devices  A general view of a computer

4. When Hardware Meets Software: A Robot Odyssey  Programs are coded instructions  Programming in PBASIC  Meet the Basic Stamp II Microprocessor  BOE: Building a mobile robot  Motors and sensors: hardware control  Robot programming: Meet the real world  Robot Exhibition: line following, obstacles

5. A Bit Further Down the Road  Looking at the bigger picture of computing  Internet: coding/decoding all the way down  Publish yourself on the web: HTML  Getting stylish, getting more control  Programming once again: Javascript  Video editing: Looks easy? Try it and see.  Video Exhibition: Show off your stuff

6. Another Approach: Computing seen from very large to very small  How about understanding computing by starting with the big picture? About people!  The largest tangible computing organization spans the entire world  Let’s start there and narrow down in search of the essentials to doing a computation  We will see this approach presents some problems!

8. Earth at Night

9. Internet Connections

11. Computer Motherboard

12. A Computer Diagram

13. Microprocessor Central Processing Unit (CPU)

14. Very Large Scale Integration View of Chip Interior

15. Individual Transistors

16. We are almost at the very bottom of the complexity tower! Question : What do we know is fundamental to (all) computers? Answer: Electricity So, to understand computers we should take the plunge and learn something about electricity.

17. Electricity and Computation (Short Version)  Electricity is the flow of electrons  Positively (+) charged areas attract electrons (-)  Conductors (metal) allow electron flow  Insulators (ceramic, air) prevent electron flow  We can control electricity by switches  Switches create a logic of on/off control  Off/on, false/true, 0/1 encodes numbers also  Arithmetic can be done using true/false logic  We can encode hardware control using 0/1’s

18. Electricity and Circuits A physical lamp circuit The corresponding schematic Single Pole-Double Throw SwitchAn LED circuit using Power/GND symbols

19. Circuits All Around You  How do I design a seatbelt safety circuit like the one in my car?  How do I add a door ajar feature as well?  How do I design a staircase lighting circuit like the one in my two story house?  What about my three story house?  What about my twelve story building?

20. What comes next?  Actually handle some components in lab and make some simple circuits: LEDs, etc  Think about how to make some useful circuits using simple switches  Combine switches to create logic circuits  Discover that logic and computation overlap in just the right way using base 2  Make a circuit that computes something!