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

Macintosh - hardware for computer animation, Macintosh - Hardware for compu...

Macintosh - Hardware for computer animation It was originally designed to be graphic and desktop publishing machines. Macs did not turn into which widely known till recently, a

Mathematical description of a perspective projection, Mathematical descript...

Mathematical description of a Perspective Projection A perspective transformation is found by prescribing a center of projection and a viewing plane. Let here assume that P(x

Explanation of light source by a luminance, Explanation of light source by ...

Explanation of light source by a luminance Explanation of any light source by a luminance the factors identified as: Light source explained by a luminance 1)   All color as

What is monitor, Q. What is Monitor? A Monitor is a television like bo...

Q. What is Monitor? A Monitor is a television like box connected to your computer and providing you a vision into the mind of your PC. It displays what your computer is thinki

Filling algorithm, Analise floodfill algirithm & boundryfillalgorithim

Analise floodfill algirithm & boundryfillalgorithim

Merits -phong shading or normal vector interpolation shading, Merits -Phong...

Merits -Phong shading or Normal Vector Interpolation Shading Hence by finding intensities at various points across the edge we determine the intensity that is varying across t

What are the important applications of computer graphics, Can you list at l...

Can you list at least three important applications of computer graphics? There are lots of interesting applications of computer graphics. Three common applications are compute

Advantages of scan line algorithm, Advantages of Scan line Algorithm:  ...

Advantages of Scan line Algorithm:   This time and always we are working along with one-dimensional array as: x[0...x_max] for color not a 2D-array like in Z-buffer algorithm.

Important points for key frame systems - computer animation, Important poin...

Important points for Key Frame Systems - Computer Animation In key frame systems the "in-between" "tweening" or frames can be created from the specification of two or more key

Frame, what is frame buffer

what is frame buffer

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