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

Characteristics of digital video, Digital video can be characterized by a f...

Digital video can be characterized by a few variables: Frame rate : various frames displayed per second. The illusion of motion may be experienced on frame rates as low as 12 f

Adobe flash - softwares for computer animation, Adobe flash - Softwares for...

Adobe flash - Softwares for computer animation Formerly, it was termed as Macromedia flash and prior to this, this was Futuresplash. This is in fact an IDE that refers to both

Low level techniques (motion specific), Low level techniques (motion specif...

Low level techniques (motion specific) Techniques utilized to fully control the motion of any graphic object in any type of animation scene, these techniques are also considere

Remark for perspective projection - transformation, Remark for Perspective ...

Remark for Perspective projection - Transformation A Perspective projection can have at most three Principle Vanishing points and at any rate one Principle vanishing point. To

What do you understand by the term image compositing, Question 1: (a) E...

Question 1: (a) Explain in detail what you understand by the term image compositing and where it is more often used? (b) You are given 3-5 images to make a photo montage/ima

Non trivial case of cohen sutherland line clippings, Non Trivial Case of co...

Non Trivial Case of cohen sutherland line clippings Case: assume for the line segment PQ, both the trivial rejection and acceptance tests failed (that is, Case 1 and Case 2

Reflection about a line - 2-d and 3-d transformations, Reflection about a L...

Reflection about a Line - 2-D and 3-D Transformations Reflection is a transformation that produces the mirror image of an object. Since we discussed that the mirror reflection

Differences of forward kinematics and inverse kinematics, Question 1: (...

Question 1: (a) Provide a clear explanation of what is ‘rigging' and its use? (b) What are the basic differences of Forward Kinematics (FK) and Inverse Kinematics (IK)? Wh

Education and training systems multimedia in education, Education and train...

Education and training systems are making with three major objectives as: a) The learning objectives and purpose of the training. b)  Assessment or testing of the students to

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