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

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

Principal vanishing point write respect to z-axis, Principal vanishing poin...

Principal vanishing point write respect to Z-axis Principal vanishing point w.r.t z-axis: By the 3rd row of matrix equation, we declare that the principal vanishing point w

Audio file formats, Audio File Formats: It is a container format for ...

Audio File Formats: It is a container format for storing audio data in a computer system. Many file formats are there for storing audio files. The common approach towards

Spline curve - modeling and rendering, Spline curve - Modeling and Renderin...

Spline curve - Modeling and Rendering Spline curve is created by using Control points that control the shape of the curve Spline curve is a composite curve formed along with s

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

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

Crt, explain the working procedure of crt digram

explain the working procedure of crt digram

Methods of animation - computer animation, Methods of Animation - Computer ...

Methods of Animation - Computer Animation First method: in this, artist makes a succession of cartoon frames that are then combined in a film. Second method: in this,

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