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

Normalization transformation, Find the normalization transformation N, whic...

Find the normalization transformation N, which uses the rectangle W(1, 1); X(5, 3); Y(4, 5) and Z(0, 3) as a window and the normalized deice screen as viewpoint.

Disadvantages of the z-buffer method, Disadvantages : 1)   Doubles memor...

Disadvantages : 1)   Doubles memory needs, one for at least z-buffer and one for refreshes- buffer. 2)   Dependency of device and memory intensive. 3) Wasted calculation u

Negative accelerations - computer animation, Negative Accelerations - compu...

Negative Accelerations - computer animation In order to incorporate decreasing speed in an animation the time spacing between the frames must decrease, thus there exists lesser

Lamberts cosine law - diffuse reflection, Lamberts Cosine Law - Diffuse Ref...

Lamberts Cosine Law - Diffuse Reflection "LAMBERTS COSINE LAW" specify that the radiant energy from any minute surface area dA in any direction θ relative to the surface usual

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

Interactive Computer Graphics, Explain the different input modes used in in...

Explain the different input modes used in interactive computer graphics.

Application of animation, Application of animation: There are a variety of...

Application of animation: There are a variety of utilizations for computer animation. They can vary from fun to practical and educational ones. Medicine, military, entertainment,

What is polygon mesh, What is Polygon mesh?  Polygon mesh is a method t...

What is Polygon mesh?  Polygon mesh is a method to show the polygon, when the object surfaces are tiled, it is more convenient to state the surface facets with a mesh function.

Transformation, determine the form of the transformation matrix for a refle...

determine the form of the transformation matrix for a reflection about an arbitrary line with equation y=mx+b.

Number system, Perform the indicated base conversions 548 to base 5

Perform the indicated base conversions 548 to base 5

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