Time delay and busy flag method, Computer Graphics

Assignment Help:

1. Using a time Delay Method

The delay required between issuing each character to the LCD is about 5-10ms (it's simply known as DELAY). When programming an LCD, a long delay is also needed for the power-up process, (it's called long delay LDELAY). For the LCD input to be enabled, the short delay is required to make the En signal wide enough.
The data is sent in nibbles in 4-bit mode. The higher nibble is sent first, and then the lower nibble. In order to enable the 4-bit mode of LCD, the follow special sequence of initialization below was used. This is also known as special reset sequence of LCD. The special reset sequence is as follows:

  1. Wait for about 20mS
  2. Then send the first init value (0x20 - for 4-bit and 0x30 for 8-bit)
  3. Wait for about 10mS
  4. Send second init value (0x20)
  5. Wait for 1mS
  6. Send third init value (0x20)
  7. Wait for 1mS
  8. Select bus width (0x20)
  9. Wait for 1mS

The busy flag will only be active after the above reset sequence is completed. The busy flag is not normally used in 4-bit mode; instead I had used a certain amount of delay usually within the range from 300 to 600us or can also write some code for reading two nibbles from the LCD. This delay might vary depending on the LCD used and crystal frequency on which LCD controller is running, but 400us usually works perfectly.

2. Using Busy Flag Method

The Data line D7 is the busy flag, and can be read when R/W=1 and RS=0. When D7 is high i.e. (busy flag =1), the LCD is busy dealing with the internal operations and will not acknowledge any new information. When D7=0, the LCD is ready to receive new information.


Related Discussions:- Time delay and busy flag method

Differentiate among interpolation and approximation spline, Differentiate a...

Differentiate among interpolation spline and approximation spline?  When the spline curve passes by all the control points then it is known as interpolate. When the curve is

Resolution, ?What is Computer Resolution?

?What is Computer Resolution?

What is the advantages of electrostatic plotters, What is the advantages of...

What is the advantages of electrostatic plotters? Advantages of electrostatic plotters: They have very high quality printers and faster than pen plotters. Recent electros

Area subdivision method for hidden surface removal, Q.  Write a short note...

Q.  Write a short note on area subdivision method for hidden surface removal.   Ans. Area Subdivision This technique for hidden- surface removal is essentially an image- spac

Engineering-applications for computer animation, Engineering: CAD has alwa...

Engineering: CAD has always been an imperative tool in industry. For illustration in automobile design, CAD could be utilized to model a car. Although with the advent of computer

Classification of print finishing processes, Problem: a. Provide exampl...

Problem: a. Provide examples of classification of print finishing processes. b. In advertising, what do you meant by creative strategies? c. Creative strategies are div

Shading - polygon rendering and ray tracing methods, Shading - Polygon Rend...

Shading - Polygon Rendering and Ray Tracing Methods When one thing is under the exposure of light, so the rays of light are distributed over the surface and there the distribu

Explain the acoustic properties of sound, Problem: (a) What is meant b...

Problem: (a) What is meant by ‘Time - Stretching ‘in relation to a sound data file? (b) Calculate the size of a 5 minutes mono sound file of CD quality and with a 16 -bit

Describe digital printing and prepress, Question 1: (a) Describe Digita...

Question 1: (a) Describe Digital Printing and Prepress? Also state the advantages and disadvantages of Digital printing? Question 2: (a) What are the three most import

Write Your Message!

Captcha
Free Assignment Quote

Assured A++ Grade

Get guaranteed satisfaction & time on delivery in every assignment order you paid with us! We ensure premium quality solution document along with free turntin report!

All rights reserved! Copyrights ©2019-2020 ExpertsMind IT Educational Pvt Ltd