1 Answer

Answer :

Liquid Crystal Display:-
An LCD is a low-cost, low power device capable of displaying text and images. LCD's are extremely common in embedded systems since such system often does not have video monitors like those that come standard with desktop systems.
LCD's can be found on numerous common device like watches, copy machine, and calculators.

Basic principle:-
The basic principle of one type of LCD, a reflective LCD, works as follows, first, incoming light passes through a polarizing plate. Next, that polarized light encounters liquid crystal material.
If we excite a region of this material, we cause the material molecules to align, which in turns causes the polarized light to pass through the material. Otherwise, the light does not pass through.
Finally, light that passed through hits a mirror and reflects back, so the excited region appears to light up.
Another type of LCD, an absorption LCD works similarly but uses a block surface instead of a mirror. The surface below the excited regions absorbs light, thus appearing darker than the other regions.
A dot-matrix LCD consists of a matrix of dots that can display alphanumeric characters (letters and digits) as well as other symbols. A common dot-matrix LCD has five column and eight rows of dots for one character. An LCD driver converts input data into the appropriate electrical signals necessary to excite the appropriate LCD dots.

image


  • Each type of LCD may be able to display multiple characters. Each character may be displayed in normal or inverted fashion.
  • The LCD may permit a character to be blinking or may permit display of a cursor indicating the current character (blinking underscore). Such functionality would be difficult for us to implement using the software.
  • Thus we use an LCD controller to provide us with a simple interface to an LCD having 8-data inputs (DB0-DB7) and one enable input.
  • To send a byte to the LCD, we provide a value to the eight inputs and pulse the enable. This byte may be a control word, which instructs the LCD controller to initialize the LCD, clear the display, select the positions of the cursor, brighten the display.
  • Alternately, this byte may be a data word, such as an ASCII characters, instructing the LCD to display the character at the currently selected display position.
  • In this example, the microprocessor is connected to an LCD controller, which in turn is connected to an LCD as shown in fig. The LCD controller receives control words from and performs the corresponding action on the LCD.
  • Once the initialization sequence is done, we can send control words as send actual data to be displayed.
  • When RS is set to low to indicate that the data sent is control word.
  • When RS is high this indicates that the data sent over the communication bus corresponds to a character that is to be displayed.
  • Everytime data is sent whether it is a control word or data, the enable bit must be toggled.
  • By using initialization code the : CD has been set with an 8-bit interface. In addition, the display has been cleared the cursor is in the home position and the cursor moves to the right as data is displayed. The LCD is now ready to be written to.
  • In order to write data, we set RS=1. The actual data we want to write is on DB0-DB7. The write char functions accept a character which will be sent to the LCD controller to display on the LCD.
  • The Enabled LCD function toggles the enables bit and acts as a delay so that the command can be processed and executed.


Like 0 like

Related Questions

Description : Liquid Crystal Display (LCD)

Last Answer : Liquid Crystal Display (LCD) LCD stands for Liquid Crystal Display. It is a flat panel electronic display device which uses light modulating properties of liquid crystal. ... pixel and passive pixel display do not consist of switch at each pixel.

Description : LCD Display Resolution

Last Answer : When you go out shopping for a new LCD TV, one of the most important things worth checking is the resolution. What's the use of an LCD when your neighbor's 20-year-old CRT has better resolution and colors? ... 1680 1050 (or WSXGA+) 24 (widescreen): 1920 1200 (or WUXGA+) 30 (widescreen): 2560 1600

Description : LCD Display Modules

Last Answer : Replacing a damaged LCD monitor is no easy task. LCDs are expensive, and so are their parts or modules. Let's take a look at a notebook computer LCD, for example. If you go ... include matrix type, viewing angle, color support, brightness, contrast ratio, aspect ratio and input ports.

Description : Industrial LCD Displays

Last Answer : Today, while the Internet has managed to steal the attention of millions of people worldwide, many still tend to turn to the TV for some good, old-fashioned quality entertainment. LCDs are in, CRT ... Some of the best manufacturers of industrial LCDs today are Viewsonic, Sony, Dell, LG and Samsung.

Description : How to Clean an LCD Screen

Last Answer : How to Clean an LCD Screen Liquid crystal display screens, more known as LCD screens, is becoming more and more popular for its higher resolutions and space-saving dimensions. However, like all appliances ... touching the screen, regular cleaning of your LCD screen will keep it doing its job well.

Description : What does the liquid crystal display require for computer applications?

Last Answer : An external light source, called a backlight.

Description : Write short notes on:  1) Phosphor characteristics  2) Liquid crystal display

Last Answer : Common computation models: Sequential program model Statements, rules for composing statements, semantics for executing them Communicating process model ... Object-oriented model For breaking complex software into simpler, well-defined pieces

Last Answer : A semaphore is called binary semaphore when its value is 0, it is assumed that it has been taken (or accepted) & when its value is 1, it is assumed that it has been released & no ... that are not themselves reentrant.3. A reentrant function may does not use the hardware in a nonatomic way.

Last Answer : The main characteristics of an embedded system are:1. Single functioned2. Tightly constrained3. Reactive and real time1. Single functioned:An embedded system usually executes a specific program repeatedly.Ex. Pager ... computer user. But it doesn't result in a system failure.Ex. Digital camera chip

Description : Define embedded system.

Last Answer : An embedded system is nearly any computing system other than a desktop computer. Embedded systems are hard to define because they cover such a broad range of electronic devices. It has three main components: 1. Hardware 2. Main application software 3. Real time operating system

Last Answer : Various features of Linux that are used in embedded systems are as follows : Linux is multiuser operating system. Linux is open source and free. Linux can be ... Linux supports handling of errors. Real-time Linux supports the group scheduling functions.

Description : Compare CRT and LCD display. 

Last Answer : CRT LCD CRT monitors require about 100 W for 19 display. LCD monitors require 45 W for 19 display. CRT's are heavier than LCD. LCD monitors are lighter and thinner They are ... is possible. CRT displays text is not good as LCD. LCD displays text better than CRTs.

Description : What is meant by embedded Linux?

Last Answer : Linux is the operating system if we use this operating system in embedded system devices then it is known as embedded Linux. Linux is open source and free.

Description : Liquid crystal elastomers 4D printing material achieve their activation due to a. Light b. Heat c. Electrical d. All of the above

Last Answer : Ans:- d. All of the above

Description : Define liquid crystal polymers.

Last Answer : Liquid crystal polymers are a class of aromatic polyester polymers which are capable of forming regions of highly ordered structure (like crystal) even in the liquid phase.

Description : State the properties of liquid crystal polymer.

Last Answer : 1) They have high mechanical strength at high temperature. 2) They are extreme chemical resistance. 3) They have good weatherability. 4) They are inert. 5) They resist stress, cracking in the ... temperatures. 6) It has high coefficient of thermal expansion. 7) It is highly resistant to fire.

Description : Define the terms: i) Photo conductive polymers ii) Liquid crystal polymers 

Last Answer : i) Photo conductive polymers: These are the polymers which conduct electricity only in the presence of light.  ii) Liquid crystal polymers: These are a class of aromatic polyester polymers. These polymers have tendency to align their chains parallel over a long distance from their melt or solution.

Last Answer : A design metric is a measure of a implementations features such as cost, size, performance and power.Commonly used design metrics are:1.NRE cost:NRE stands for non recurring engineering cost. ... to check that manufacturing was correct.11.Safety:The probability that the system will not cause harm.

Description : What is a hard real time system?

Last Answer : If the real-time systems have minimum interrupt latency and task deadline with prescribe time limits then it is known as hard real-time systems.  If these two requirements meet in real time systems but not always then it is known as soft real-time systems.

Description : Which crystal system minerals are isotropic? a) monoclinic b) orthorhombic c) hexagonal d) cubic

Description : What is the theoretical limit of the efficiency of a single-crystal single-junction cell in a photovoltaic system? w) 9 percent x) 29 percent y) 79 percent z) 99 percent

Last Answer : ANSWER: X -- 29 PERCENT

Description : What is a LCD Monitor?

Last Answer : Ans. LCD Monitor is commonly used in portable computer and it creates images with a special kind of liquid crystal that normally transparent but becomes opaque when charged with electricity.

Description : In microcontroller and LCD interface which line will instruct the LCD that microcontroller is sending data? a) DB0 b) RW c) EN d) RS

Last Answer : d) RS

Description : Interfacing LCD with 89C51 _____ data lines are used along with the _____ signals. a) 6, RS, RW b) 5, RW, EN c) 8, RS, EN, RW d) 9, RS, EN, RW

Last Answer : a) 6, RS, RW

Description : Give any two applications of LED and LCD each. 

Last Answer : Two applications of LED (1) As an indicators and small display. (2) In digital thermometer, pulse rate meter. (3) In patient monitoring. Two applications of LCD (1) In video games (2) In calculators (3) In test equipments (4) In gauges and counters

Description : Differentiate between LCD and LED TV.

Last Answer : Differentiate between LCD and LED TV.

Description : State any four characteristics of LCD monitor.

Last Answer : Characteristics of LCD Monitor 1. Pixels: This refers to an individual dot on the screen. All graphics displayed on the screen are composed of hundreds or thousands of these graphic dots or pixels or pet. ... takes for a pixel to go from black to peak intensity white and then back to black again.

Description : Explain working principle of LCD monitor. 

Last Answer : Backlight: The amount of light supplied by Back Light is determined by the amount of movement of the liquid crystals in such a way as to generate color. Driving Circuit Unit Driving ... color LCD is subdivided into three subpixels, where one set of RGB subpixels is equal to one pixel.

Description : Explain Passive matrix LCD with diagram.

Last Answer : Passive Matrix: Passive-matrix is a technology that uses a grid of vertical and horizontal wires to display an image on the screen. Each pixel is controlled by an intersection of two wires in the grid. ... are no switching devices, and each pixel is addressed for more than one frame time. 

Description : Draw interfacing of 16 × 2 LCD with 8051 and state the function of EN and RS of LCD

Last Answer : Diagram: RS: RS is the register select pin. We need to set it to 1, if we are sending some data to be displayed on LCD. And we will set it to 0 if we are sending some command instructions ... the LCD to latch in the data present at the data pins. This pulse must be a minimum of 450ns wide.

Last Answer : LED is better than LCD. LED have lots of advantages and LED have long span .

Description : The DMA controllers are special hardware embedded into the chip in modern integrate processor that ____and_____ to the system; a. Data transfer b. arbitrate access c. Both A and B d. None of these

Last Answer : c. Both A and B

Description : Can you use an Earthing sleep system over a mattress pad that has magnets embedded in it?

Last Answer : There is no A. There is no problem with using an Earthing sheet problem with using an Earthing sheet over a magneti over a magnetic mattress pad. The magnets c mattress pad. The magnets in the ... similar to the way it passes through ilar to the way it passes through a regular a regular sheet.

Description : In term of Digital evidence, the internet is an example of a. Open computer System b. Communication System c. Embedded Computer System d. None of the above

Last Answer : b. Communication System

Description : 3. In term of Digital evidence, a mobile telephone is an example.of a. Open Computer System b. Communication System c. Embedded Computer System d. None of the Above

Last Answer : c. Embedded Computer System

Description : In term of Digital evidence, a hard drive is example.of a. Open Computer System b. Communication System c. Embedded Computer System d. None of the Above

Last Answer : a. Open Computer System

Description : is a branch of Science which deals with the helping machine find solutions to complex problems in a more human like fashion a. Artificial Intelligence b. Internet Od Things c. Embedded system d. cyber Security

Last Answer : a. Artificial Intelligence

Description : The term of digital evidence, the internet is an example of (a) Open computer system (b) Communication system (c) Embedded system (d) None of these

Last Answer : (b) Communication system

Description : In term of digital evidence , a smart card of use of example of (a) Communication system (b) Open system (c) Embedded system (d) None of above

Last Answer : (c) Embedded system

Description : The term of digital evidence the internet is an example of (a) Open computer system (b) Communication system (c) Embedded system (d) None of thes

Last Answer : (b) Communication system

Description : 2) Digital evidence , a hard drive is a example (a) Open computer system (b) Communication system (c) Embedded system (d) None of these

Last Answer : (a) Open computer system

Description : A digital multi meter is an example of an embedded system for A. Data communication B. Monitoring C. Control D. All of these

Last Answer : B. Monitoring

Description : What are the essential tight constraint/s related to the design metrics of an embedded system? A. Ability to fit on a single chip B. Low power consumption C. Fast data processing for real-time operations D .All of the above

Last Answer : D .All of the above

Description : Which of the following is (are) example(s) of embedded system for data communication? A. Network router B. Digital camera C. Music player D. All of these

Last Answer : B. Digital camera

Description : The first mass produced embedded system is A. Minuteman-I B. Minuteman-II C. Autonetics D-17 D. Apollo Guidance Computer (AGC)

Last Answer : C. Autonetics D-17

Description : The first recognized modern embedded system is A. Apple computer B. Apollo Guidance Computer (AGC) C. Calculator D. Radio navigation system

Last Answer : B. Apollo Guidance Computer (AGC)

Description : Which of the following is not an example of a “small-scale embedded system”? A. Electronic Barbie doll B. Simple calculator C. Cell phone D. Electronic toy car

Last Answer : C. Cell phone

Description : Which of the following is not true about embedded systems? A. Built around specialized hardware B. Always contain an operating system C. Execution behavior may be deterministic D. None of these

Last Answer : D. None of these

Description : Embedded system is______ A. An electronic system B. A pure mechanical system C. An electro-mechanical system D. (A) or (C)

Last Answer : D. (A) or (C)

Show MoreNext Page → ← Prev Page