1. COSMOS Summer 2008 Necessary Electronics
Rajesh K. Gupta
Computer Science and Engineering
University of California, San Diego.
2008 R. Gupta, UCSD

2. Roadmap Topic: This lecture Next lecture Reference Keywords:
Electronics you need to know
This lecture
Concepts covered: “Open Drain”, Clock, Memory, Address Space
Next lecture
The I2C Interface
Reference
None
Keywords:
Electrical Signals
Circuit Schematics,
DRAM, Flash memories
Resistors, Capacitors,
Analog, Digital Waveforms,
2008 R. Gupta, UCSD

3. A bit about electronics
Electronics is all about movement or storage of electrons (Negatively charged particles)
A collection of electrons represents a certain amount of charge
A collection of charge creates an electrical field around it
Since charges attract or repel each other, this is expressed as a voltage difference that makes a charged particle to move
An electron moves from low voltage to high voltage
Which is same as a current movement from high voltage to low voltage.
2008 R. Gupta, UCSD

4. A bit more
Electrical current is caused by movement of electrons in an electric field
Voltage, Current and Ohm’s Law
Reference Voltages: Power, Ground
An electrical circuit represents a complete path for flow of current
A signal waveform represents change of voltage at a point in a circuit over time
DC and AC components of a waveform. Analog versus Digital.
Finally, what are circuit schematics? Components.
2008 R. Gupta, UCSD

5. Some Common Components
Passives
Resistors, Potentiometers
Capacitors
Inductors
Actives
Diodes, LED
Transistors
Crystals, Oscillators
2008 R. Gupta, UCSD

6. Questions to ponder Communications? What and How
Among humans
Among machines
What are the possible ways machines can communicate?
What medium do they use? Electrical wire or wireless
What do they communicate? Analog versus digital
How they communicate? Serial versus Parallel
What else?
2008 R. Gupta, UCSD

7. A Processor’s Interfaces
We talked about Memory last time: RAM, ROM
What are various memory blocks?
DRAM, SRAM, Flash
How is a memory ‘addressed’?
What is an address space?
How do we communicate to a ‘peripheral’?
2008 R. Gupta, UCSD

8. Recap
Electrical signaling typically consists of voltage change waveform over time
Can be analog or digital
Computers interfaces with devices via memory or via direct ports
Next: I2C interface.
2008 R. Gupta, UCSD