DIDGITAL SYSTEMS Flashcards
What is a combinational circuit and give an example
logic gates whose output at any immediate time is determined by the present input ONLY (no memory)
An example of a combinational circuit is a decoder.
Another example is the multiplexer
What is a sequential circuit? Give examples
A circuit whose output at any immediate time depends not only on the input present but also on the past output
(hence, a memory element).
Examples of sequential circuits are flip-flop, register, counter, clocks, etc.
What are semiconductor memory technologies and give examples
Semiconductor memory is a type of semiconductor device tasked with storing data. There are two electronic data storage mediums that we can utilize, magnetic or optical.
Eg ROM, RAM, EPROM, EEPROM, Flash memory, DRAM, SRAM, SDRAM,
What is a finite state machine and what are its applications?
a computation model used to implement hardware or software where sequential logic and computer programs are simulated.
Finite state machines can be used to model problems in many fields including mathematics, artificial intelligence, games, and linguistics.
Give a brief history of computers
- Vacuum tubes, punch cards
2.Transistors
3.Integrated circuits
ICs just kept growing: large-scale integration (LSI), more than 1,000,000 components; Very-large-scale integration (VLSI) achieved more than 1,000,000,000
components per chip,
What is an integrated circuit?
An integrated circuit (IC) is a small semiconductor-based electronic device consisting of fabricated transistors, resistors and capacitors.
Describe the von Neuman architecture and illustrate with a diagram
Consists of:
• A main memory, which stores both data and instructions.
• An arithmetic-logical unit (ALU) capable of operating on binary data.
• A control unit.
• Input and output (I/O) equipment operated by the control unit.
*See notes for diagram
What are some of the Desktop applications that require the great power of today’s microprocessor-based systems
- Image processing
- Speech recognition
- Videoconferencing
- Multimedia authoring
- Voice and video annotation of files
- Simulation modeling
What is Moore’s law
the number of transistors in a dense integrated circuit (IC) doubles about every two years
What are the three approaches to increasing microprocessor speed
1.Increase the hardware speed of the processor.
2.Increase the size and speed of caches that are interposed between the processor and main memory.
-In particular, by dedicating a portion of the processor chip itself to the cache, cache access
times drop significantly.
3.Make changes to the processor organization and architecture that increase the effective speed of instruction execution.
What is an obstacle brought about by increasing speeds?
Power: As the density of logic and the clock speed on a chip increase, so does the power density.
Describe RC delay
R = resistance. As components on the chip decrease in size, the wire interconnects become thinner, increasing
resistance.
C = capacitance Also, the wires are closer together, increasing capacitance.
RC delay = the delay in signal speed through the circuit wiring as a result of these two effects. It can become a significant obstacle to continued downward scaling of logic and memory devices
Describe memory latency
Memory speeds lag processor speeds.
What is pipelining?
A pipeline works much as an assembly line in a manufacturing plant enabling different stages of
execution of different instructions to occur at the same time along the pipeline.
What is the superscalar approach
A superscalar approach in essence allows multiple pipelines within a single processor so that instructions that do not depend on one another can be executed in parallel.
