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

Three sub-fields of computer simulation, Three Sub-Fields of Computer Simul...

Three Sub-Fields of Computer Simulation Computer simulation is the electronic equivalent of this kind of role playing and it functions to drive synthetic environments and virt

Categories of line segments - 2d clipping algorithms, Categories of Line Se...

Categories of Line Segments It categorizes line segments into three categories (i) trivially rejected (ii) trivially selected (iii) may be partially visible or totally invisibl

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

What are the steps involved in 3d transformation, What are the steps involv...

What are the steps involved in 3D transformation?  Modeling Transformation Projection Transformation Viewing Transformation Workstation Transformation

Translation, Translation, Rotation and Scaling -  output primitives 1. ...

Translation, Rotation and Scaling -  output primitives 1. Two basic approaches used in character generation are - Bitmap method and outline method.  2. All 2D geometric tran

Time based and presentation tools, Time Based and Presentation Tools In...

Time Based and Presentation Tools In such authoring systems, components and events are organized beside a timeline, along with resolutions as high as 1/30 second. Time based to

Serial line db9 connector, Main Objectives of this connector is to allow fu...

Main Objectives of this connector is to allow full duplex communication between peripherals that uses such connector such PIC Demo board, ICD2 Debugger etc. The RS32 connector pin

Define coherence properties, Define coherence properties?  A coherence ...

Define coherence properties?  A coherence property of a scene is a part of a scene by which relate single part of the scene with the other parts of the scene.

Types of polygon tables curves and surfaces, Types of Polygon tables curves...

Types of Polygon tables curves and surfaces Attribute tables: This table has object information as transparency, surface reflexivity, texture features of an object in the vi

Computational algorithm for simulating physical system, computational algor...

computational algorithm for simulating the behavior of different physical and mathematical systems Monte Carlo methods are an extensively utilized class of computational algor

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