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

Orthographic and oblique projection - viewing transformation, Orthographic ...

Orthographic and Oblique Projection - Viewing Transformation Orthographic projection is the easiest form of parallel projection that is commonly utilized for engineering drawi

Basic structures for multimedia interactive applications, Question: (a)...

Question: (a) Sound often gives the only effective way to convey an idea, elicit an emotion, or dramatise a point. Explain two situations of the use of sound that would be con

Digital video, Digital Video: Digital video is a form of video record...

Digital Video: Digital video is a form of video recording system which works through using a digital, quite than analog, representation of the video signal. It generic means,

List five different area of application of computer graphics, Question: Lis...

Question: List five different areas of applications of computer graphics Answer: Five major areas of applications of computer graphics are:  i) Study of molecular structures.

Computer science, what do you means by bresenham s him algorithm

what do you means by bresenham s him algorithm

What is graphics, What is Graphics It is a term that refers to any com...

What is Graphics It is a term that refers to any computer device or program which makes a computer able of displaying and manipulating pictures. The name also refers to the im

Identify design patterns, Mauri Ltd has just acquired a new stock manageme...

Mauri Ltd has just acquired a new stock management system and the source codes (PhP5) also have been delivered. The coding style is fully object-oriented. The company has been u

Construction of an isometric projection - transformation, Construction of a...

Construction of an Isometric Projection - Transformation In this projection, the direction of projection i.e. d = (d 1 ,d 2 ,d 3 ) makes an identical angles with all the 3-pr

Simulation-applications for computer animation, Simulation: There are seve...

Simulation: There are several things, places and events people cannot witness in first person. There are a lot of causes for this. Several may happen too rapidly, several may be t

Demerit - phong shading or normal vector interpolation shadi, Demerit - pho...

Demerit - phong shading or normal vector interpolation shading Needs lot of computations to determine intensity at a point, hence increases the cost of shading in any impleme

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