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

Introduction of visible surface detection, Introduction of Visible Surface ...

Introduction of Visible Surface Detection For displaying a realistic presentation of the given 3Dimentional object, hidden surfaces and hidden lines should be identified fo

Three sub-fields of computer simulation, Three Sub-Fields of Computer Simul...

Three Sub-Fields of Computer Simulation Computer simulation is the electronic equivalent of this kind of role playing and it functions to drive synthetic environments and virt

Compute the position of the car on the road, An animation demonstrates a ca...

An animation demonstrates a car driving along a road that is given by a Bezier curve along with the subsequent control points:  X k 0 5

Rotation - 2-d and 3-d transformations, Rotation - 2-d and 3-d transformati...

Rotation - 2-d and 3-d transformations Given a 2-D point P(x,y), that we want to rotate, along with respect to an arbitrary point A(h,k). Suppose P'(x'y') be the effect of ant

Explain about the computer based training, Explain about the Computer Based...

Explain about the Computer Based Training CBT makes use of a computer system to train people in numerous applications. It makes use of self-assessment and multimedia with minim

Graphics, GRAPHICS: It is one of the core elements of any multimedia ...

GRAPHICS: It is one of the core elements of any multimedia application. We all have heard a well-known saying as "one picture conveys a message of 1000 words", hence without

Please give me ans, Differences between digital differential analyzer and ...

Differences between digital differential analyzer and VECGEN line algorithm?

Rotation about an arbitrary axis, Rotation about an arbitrary axis Rota...

Rotation about an arbitrary axis Rotation about an arbitrary axis is a composition of several rotations and translation operations. What you need to do is the following:  a)

Photo editing, Photo Editing Photo-editing programs are paint programs...

Photo Editing Photo-editing programs are paint programs: it just like they comprise several sophisticated functions for altering images and for scheming aspects of the image,

Odd-even rule and non-zero winding number rule, What is the difference betw...

What is the difference between odd-even rule and non-zero winding number rule to identify interior regions of an object? Develop an algorithm for a recursive method for filling a 4

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