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

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

Basic structures for multimedia interactive applications, Question: (a)...

Question: (a) Sound often gives the only effective way to convey an idea, elicit an emotion, or dramatise a point. Explain two situations of the use of sound that would be con

Define b-spline curve, Define B-Spline curve?  A B-Spline curve is a se...

Define B-Spline curve?  A B-Spline curve is a set of piecewise (usually cubic) polynomial segments that pass close to a set of control points. Though the curve does not pass by

Briefly explain types of animation, Question 1 Briefly explain types of an...

Question 1 Briefly explain types of animation Question 2 Briefly explain steps involved in animation process Question 3 What is Layout? Explain two types of layout

Transformation regarding to the mirror reflection to line, The transformati...

The transformation regarding to the mirror reflection to this line L comprises the subsequent basic transformations: 1) Translate the intersection point A(0,c) to the origin, it

Painting and drawing tools in multimedia, Painting and Drawing Tools Pa...

Painting and Drawing Tools Painting software is offered to producing crafted bitmapped images. Drawing software as Corel Draw and Canvas is offered to generating vector depend

Softwares for computer animation, Software for computer animation Wh...

Software for computer animation Whether you might have the excellent hardware in the world, but without a high-quality software package, your hardware can act nothing. There

Microcomputer applications, Calculate how many customers there are for each...

Calculate how many customers there are for each lawn size. Name this sheet

What is raster scan display, What is  Raster Scan Display A raster sca...

What is  Raster Scan Display A raster scan display device using CRT on the other hand directs the electron beam across the screen, one row at a time from top to bottom. In a ra

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