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

Cel animation - computer animation, Cel Animation - Computer Animation ...

Cel Animation - Computer Animation Making an animation by using this method, all characters are drawn on a separate piece of transparent paper. Also a background is drawn on a

Matrix for orthographic projection, Matrix for Orthographic Projection ...

Matrix for Orthographic Projection Orthographic projections are projections into one of the coordinate planes x=0, y=0or z=0. The matrix for orthographic projection on the z=0

Optical character recognition software, Optical Character Recognition Softw...

Optical Character Recognition Software (OCR) Frequently, you will have printed matter and the other text to incorporate in your project although no electronic text file. Along

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

Prepare a cylinder, Question: (a) Write a short note on the dot syntax...

Question: (a) Write a short note on the dot syntax as used in actionScript. (b) A data type describes the kind of information a variable or ActionScript element can hold.

Avi codec format, AVI CODEC Formats: Various AVI file formats other than t...

AVI CODEC Formats: Various AVI file formats other than the DV Types 1 and 2 formats are there discussed earlier. All such the other formats involve the utilization of Compressor o

Structural links, Structural Links: The information contained inside the h...

Structural Links: The information contained inside the hypermedia application is classically organized in several suitable fashions. This organization is represented by using stru

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

Acquire a transformation matrix for perspective projection, Acquire a trans...

Acquire a transformation matrix for perspective projection for a specified object projected onto x=3 plane as viewed by (5,0,0). Solution: Plane of projection: x = 3 as given.

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