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

Polygon representation methods - modeling and rendering, Polygon Representa...

Polygon Representation Methods - Modeling and Rendering Any scene to be created by computer graphics may include a variety of objects, a few of them natural and manmade. Hence

Non-zero accelerations - computer animation, Non-Zero Accelerations - Compu...

Non-Zero Accelerations - Computer Animation This method of simulating the motion is fairly helpful introducing the realistic displays of speed changes, particularly at the sta

Animation tools, Animation Tools: Hardware tools: PCs ,Macintosh, ...

Animation Tools: Hardware tools: PCs ,Macintosh, Amiga Software tools: -          Softimage ( Microsoft) ; -          Alias/ Wavefront ( SGI) -          3D s

Computations with phong shading, Computations with Phong Shading Compu...

Computations with Phong Shading Computations involved along with Phong Shading:  i)   Find out average unit normal vector at each polygon vertex. ii)   Linearly interpol

Need for video compression, Need for Video Compression: T he high bit ...

Need for Video Compression: T he high bit rates that result from the various types of digital video make their transmission through their intended channels very difficult. Eve

Scenes - polygon rendering and ray tracing methods, Scenes - polygon render...

Scenes - polygon rendering and ray tracing methods In the context of ray tracing, a scene is a set of objects and light sources which will be viewed through a camera. All of

Other video file formats, Other Video File Formats: There are several the ...

Other Video File Formats: There are several the other formats for storing video in the digital formats. Such formats are usually used for the storage and viewing of video through

Calculate the gray level value for all the pixels, An 8x8 image f[i,j] has ...

An 8x8 image f[i,j] has gray levels given by the following equation: f [i , j]= ? i-j ? ; i,j=0,1,2,3,4,5,6,7. a. Calculate the gray level value for all the pixels in the 8x8

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.

Explain briefly ancillary operations, Problem: a. Explain briefly six A...

Problem: a. Explain briefly six Ancillary Operations? b. When do ancillary operations take place? c. (i) What is flexography? (ii) Provide examples of finished produ

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