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

Geometric tables - polygon tables, Geometric tables - Polygon Tables ...

Geometric tables - Polygon Tables 1) Vertex table: Keep vertices' coordinates values in the object. 2) Edge table: Keep pointers back in to the vertex table for identif

Time delay and busy flag method, 1. Using a time Delay Method The delay...

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

How does resolution of a system influence graphic display, 1. How does the...

1. How does the resolution of a system influence graphic display? Ans. In a high resolution system the adjacent pixels are so near spaced such approximated line-pixels lie extr

Design a game using graphical user interface, BlackJack is a popular card g...

BlackJack is a popular card game played in many casinos. The player plays against the dealer aiming to reach 21 points, or a score higher than the dealer without exceeding 21. The

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,

Positioning Techniques, Explain Positioning Techniques in computer Graphics...

Explain Positioning Techniques in computer Graphics in detail

B-spline curves - clipping and 3d primitives, B-spline curves - clipping an...

B-spline curves - clipping and 3d primitives B-spline curves are piecewise polynomial cubes with one or more polynomial pieces with a minimum smoothness requirement.  For examp

Combination of positive and negative accelerations, Combination of Positive...

Combination of Positive and Negative Accelerations Actually, it is not that a body once decelerated or accelerated will remain so, although the motion may include both speed-up

Identify what the use of homogenous co-ordinates, 1. Why are homogeneous co...

1. Why are homogeneous co-ordinates utilized in computer vision? I want to identify what the use of homogenous co-ordinates makes possible in terms of camera models. 2. Consider

Introduction of curves and surfaces, Introduction of Curves and Surfaces ...

Introduction of Curves and Surfaces This section has covered the methods of generating polygons, closed and curves surfaces. Under those methods we have discussed different ty

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