Unit 2: Interfacing
What is Interfacing?
The design of the interconnections between circuits that shifts the levels of voltage and current to make them compatible.
Other Digital IC Specifications
Driver Capabilities:- sometimes referred to as Fan-In or Fan-Out
Fan Out:- number of inputs of a logic family that can be driven by single output. The drive capability of outputs
Fan In:- the load an input places on an output
Propagation Delay:- has to do with the "speed" of the logic element
Power Dissipation:- generally, as propagation delays decrease, power consumption and heat generation increase. CMOS is noted for low power consumption.
Transistor–Transistor Logic(TTL)
The design of the interconnections between circuits that shifts the levels of voltage and current to make them compatible.
Other Digital IC Specifications
Driver Capabilities:- sometimes referred to as Fan-In or Fan-Out
Fan Out:- number of inputs of a logic family that can be driven by single output. The drive capability of outputs
Fan In:- the load an input places on an output
Propagation Delay:- has to do with the "speed" of the logic element
Power Dissipation:- generally, as propagation delays decrease, power consumption and heat generation increase. CMOS is noted for low power consumption.
Transistor–Transistor Logic(TTL)
- A widely used technology for making integrated circuits
- Employs transistors with multiple emitters in gates having more than one input.
- TTL ICs usually have four-digit numbers beginning with 74 or 54.
- Is a technology for constructing integrated circuits
- CMOS technology is used in microprocessors, micro-controllers, static RAM, and other digital logic circuits
- It is also used for several analog circuits such as image sensors, data converters, and highly integrated transceivers for many types of communication
- Mechanical switchers that serve as inputs for some digital circuits(like counters) may need switch debouncing
- Low to High switch transition can result in H-L-H bounces
- Demonstration of a debouncing circuit in action
- Is a semiconductor device used to amplify and switch electronic signals and electrical power
- A voltage or current applied to one pair of the transistor's terminals changes the current through another pair of terminals
- Some transistors are packaged individually, but many more are found embedded in integrated circuits
- A motor that rotates a fixed angle for each input pulse
- The logic levels applied to each field coil are defined in the Control Sequence for the stepper motor
- Can reverse direction by progressing either up or down the control sequence
- A motor widely used in radio-control vehicles that rotates to an angle defined by the pulse width of the input signal
- It is driven by Pulse-Width Modulation
- The pulse widths for hobby servo motors range from about 1-to-2mSec
- Limited range of rotation such as 180 degrees