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

What is shearing, What is shearing?  The shearing transformation actua...

What is shearing?  The shearing transformation actually slants the object with the X direction or the Y direction as needed.ie; this transformation slants the shape of an obje

Mpeg-2 , MPEG-2 : MPEG-2 that is Moving Picture Experts Group format 2 is ...

MPEG-2 : MPEG-2 that is Moving Picture Experts Group format 2 is the standard used through DVD and is of a much higher quality than MPEG- 1. This format gives for 720 x 480 resolu

Shearing - 2-d and 3-d transformations, Shearing - 2-D and 3-D transformati...

Shearing - 2-D and 3-D transformations Shearing transformations are utilized for altering the shapes of 2 or 3-D objects. The consequence of a shear transformation seems like

What makes a pattern a pattern, QUESTION (a) Suppose that you have been...

QUESTION (a) Suppose that you have been assigned to re-engineer the existing systems for a company. Do you think that design patterns can be applied to these existing systems?

Displacement mapping, Implement displacement mapping and bump mapping on a ...

Implement displacement mapping and bump mapping on a sphere. The displacement can be whatever your choice. The bump map can be whatever your choice as well.

Hypertext, Hypertext: it is conceptually very similar as regular text: it ...

Hypertext: it is conceptually very similar as regular text: it can be stored, searched, read, or edited along with a significant difference: hypertext is text along with pointers

Explain about the computer-aided design, Explain about the Computer-Aided D...

Explain about the Computer-Aided Design CAD is used in the design and development of new products in a several of applications both at home and on a commercial/industrial basis

3D transformation, what are the steps involved in 3D transformation

what are the steps involved in 3D transformation

Chemistry-applications for computer animation, Chemistry: Computer animati...

Chemistry: Computer animation is a very helpful tool in chemistry. Several things in chemistry are too small to see, and handle or do experiments on like, molecules and atoms for

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