Published on

ENGN4213 wk1 Tuesday

Table of Contents

Digital vs Analog

  • Analogue circuit hard to change once manufactured. Digital circuits can be reprogrammed
  • Analogue circuits are less noise-tolerant and can have varying performance
  • Complex analogue circuits can take up large amounts of space. Digital can perform the same functions, while being a fraction of the size

Field-Programmable Gate Arrays (FPGAs)

  • Integrated circuits of arrays of configurable logic blocks
    • Interface to the outside world via I/O Blocks
  • Blocks can be configured to perform basic combinatorial logic operations
  • Multiple logic blocks can be combined through series and/or parallel interconnections

Microprocessors

  • Special type of digital systems designed to perform or execute a limited set of operations (instructions)
  • Can combine instructions to perform complex tasks

FPGAs vs Microprocessors

  • FPGAs have parallel and deterministic architectures -> Good for low-latency, high-throughtput applications not implementable by a CPU
  • CPUs are often deployed alongside FPGAs in embedded applications

Hardware Description Language (HDL)

  • Using Verilog in this course

Digital circuits

  • Analysed in terms of logic values:
    • 0/1, LOW/HIGH, ON/OFF, etc

Logic Levels

  • VddV_dd -> Supply voltage: 5.0V
  • VIHV_IH -> Min input voltage: 3.5V, recognised as high
  • 1.5V to 3.5V recognised as undefined
  • VILV_IL -> Max input voltage: 1.5V, recognised as low
  • VSSV_SS -> Reference: 0.0V

Transition Time

  • Transition of output between logic LOW and HIGH is ideally instantaneous.
    • Nonzero transition times are caused maily by capacitance in the circuit and/or the load
  • A chain of logic gates, each with nonzero transition time, will introduce a propagation delay
  • Slow transitions and/or propagation delays can affect the ability of a circuit to operate at a certain frequency