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

De casteljeau algorithm - bezier curves, De Casteljeau algorithm: The cont...

De Casteljeau algorithm: The control points P 0 , P 1 , P 2 and P 3 are combined with line segments termed as 'control polygon', even if they are not actually a polygon although

Historical method – oral tradition, Historical method - Oral tradition: ...

Historical method - Oral tradition: Only the teacher was the source of information The teacher treated as a role model. The teacher was the main resource to meet indiv

Icon based or event driven tools, Icon Based or Event Driven Tools In s...

Icon Based or Event Driven Tools In such authoring systems, multimedia components and interaction cues or events are organized like objects in a structural process or framework

Boundary-fill algorithm or flood-fill algorithm , boundary-fill algorithm o...

boundary-fill algorithm or flood-fill algorithm As you saw the implementation of scan line polygon fill requires that boundaries should be straight line segments.  The seed fi

Write short notes on rendering bi-cubic surface, Write short notes on rende...

Write short notes on rendering bi-cubic surface patches of constant u and v method?  The simple way is to draw the iso-parmetric lines of the surface. Discrete approximations t

Objectives of three dimensional transformations, Objectives  of Three dimen...

Objectives  of Three dimensional transformations explain basic 3D transformations-translation, rotation, scaling, shear and reflections-applied to objects in space; ex

Scan line polygon fill algorithm - raster graphics, Scan Line Polygon Fill ...

Scan Line Polygon Fill Algorithm - Raster Graphics In such algorithm, the information for a solid body is stored in the frame buffer and utilizing that information each pixel

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