Programming lcd in 4 bit and 8 bit mode using 8051

We use LCD display for the displaying messages in a more interactive way to operate the system or displaying error messages etc. Hence, in this project, I will not only give the information of LCD and also provide the code in C language which is working fine without any errors.

There are 16 pins in the LCD module, the pin configuration us given below. During the initializing sequence and other commands this pin should low. A high to low pulse of about ns pulse is given to this pin. So by reading the above table you can get a brief idea how to display a character.

For displaying a character you should enable the enable pin pin 6 by giving a pulse of ns, after enabling the pin6 you should select the register select pin pin4 in write mode. Follow these simple steps for displaying a character or data. To send a command to the LCD just follows these steps:. Commands: There are some preset commands which will do a specific task in the LCD.

programming lcd in 4 bit and 8 bit mode using 8051

These commands are very important for displaying data in LCD. The list of commands given below:. To get the detailed information, Click Here and Download the Datasheet. Coming to the programming you should follow these steps:. To initialize LCD to the the following instruction and commands are to be embed in to the functions.

The programs given below will use above functions and display the complete string which is given by the programmer to display the data. We have provided two demo codes working properly and easy to understand. Below is a simple code written in assembly using keil. The code is written for uc. For info on pin connections or other things,email me- srihariash gmail.

Hi…sir am pratibha…we are ding LCD display project we want code and diagram plz give me. Sir I am designing digital presaure measurment display…I am confuse that I give a anlog signal to adc and it convert that into digital and I want to display preesure according to signal applied to the adc how can I do that.?? I want to read real time values from sensors through microcontroller and display it here.

Will this code work or if no then can anyone help me with the code in keil vision software. Your email address will not be published. Table of Contents. Comments hi…. Wow, this article is good, my sister is analyzing such things, thus I am going to let know her. This is the best code I found over internet. Leave a Reply Cancel reply Your email address will not be published. Change Ad Consent. RS is the register select pin used to write display data to the LCD charactersthis pin has to be high when writing the data to the LCD.InterfaceLCD.

This post documents the steps involved in interfacing the LCD in 4 bit mode with a microcontroller. It belongs to a series of 4 posts. If you landed here straight from a search engine, here is an index to help you navigate. Embedded applications are always developed on controllers whose resources are almost fully used in order to cut the cost of the product. This is done especially in applications that do not need any future expansions or a firmware updates.

They are Make-it and Forget-it kind of applications. Most of the time, either the memory or the available pins are in demand. In some cases both memory and pin count are less. The Character LCD in 8 bit mode uses 8 data lines and 3 control lines to display characters. This kind of interface is costly in terms of pin usage.

Most of the industrial applications use the LCD in 4 bit mode. The total data lines needed is reduced by half in this mode. I have already discussed this in one of my previous posts on the Theory behind the LCD modules. By doing this we mean that the LCD will always be operated in Write mode and Read mode will not be used.

This way another pin can be saved. The interface of LCD in 4 bit mode without checking for busy flag can be little tricky and we have to give enough delays calls between data latch and next data write to insure that the LCD is never busy while a new data is written to it.

Hence this interface will just use 6 pins of the interface. The 8 bit data is split up into two chucks of 4 bits each. The higher nibble is sent first and then the lower nibble is sent to make one complete data transfer. Since each byte is transferred in two steps the speed of this method will theoretically be doubled. Also, we are not using the busy flag to monitor the state of the LCD so this introduced a further reduction the speed of the execution.

The connection is really simple and it is quit self explanatory. Here are some images to help understand the wiring better. So you will notice that I am not connecting anything to those pins. In the above image you can see 7 wires that are connected to the Male Header pins. Here is the entire setup. Here also we will be using the same functions. Only the lcd. Also most of the function and how they behave has been discussed in my previous post, programming LCD in 8 bit mode.

So I will not rehash them here and make this post lengthy. Note: The delay function call will vary from one oscillator frequency to another.As per the name the 2x16 has 2 lines with 16 chars on each lines. It supports all the ascii chars and is basically used for displaying the alpha numeric characters. Here each character is displayed in a matrix of 5x7 pixels.

Apart from alpha numeric chars it also provides the provision to display the custom characters by creating the pattern. Data Bus: As shown in the above figure and table, an alpha numeric lcd has a 8-bit data bus referenced as D0-D7. Below schematic shows the minimum connection required for interfacing the LCD with the microcontroller. The below configuration is as per the above schematic.

First lets see the timing diagram for sending the data and the command signals RS,RW,ENaccordingly we write the algorithm and finally the code.

The below image shows the timing diagram for sending the data to the LCD. As shown in the timing diagram the data is written after sending the RS and RW signals. It is still ok to send the data before these signals.

The only important thing is the data should be available on the databus before generating the High-to-Low pulse on EN pin. The timings are similar as above only change is that RS is made high for selecting Data register.

In the above tutorial we just discussed how to interface 2x16Lcd in 8-bit mode. Once you know the working of lcd, you can directly use the ExploreEmbedded libraries to play around with your LCD. For that you need to include the lcd. After including these files, the only thing you got to do is to configure the PORTs in lcd. The below sample code shows how to use the already available LCD functions.

Download the complete project folder from the below link: Hardware design Files and Code Library. Have a opinion, suggestionquestion or feedback about the article let it out here!Hello there!! As you all know LCD stands for liquid crystal display. Other reason is we can print various characters on the screen. It has 2 rows and 16 columns. Each block has certain number of pixels. You can draw your own character by saving the pattern of pixels.

First things first lets get the datasheet. The link is : Datasheet Link. Please download the datasheet because a datasheet tells you everything there is to know the electrical parameters, command registers, pin-outs and so on. Now there is a protruding rectangular portion on this LCD.

This will help you identify which pin is which. Now let us see what each pin does exactly.

INTERFACING LCD WITH 8051 MIROCONTROLLER with code

But then they have also printed 16 and 1 on the back of LCD, so no need to worry about connecting the pins inverted.

The pin features are explained in the table. The contrast adjust input is nothing but output taken from a pot. So basically when you vary the potyou get different values of voltage from the voltage divider network. And thus you can change the contrast to suit your visual needs. Your LCD may get damaged.

DB0 to DB7 are the databus lines. You send the command word as well as the data to be written on this bus. RS : This stands for register select.

The read is active high signal and write is active low. Thus when you want to read from the LCD you make the signal on this pin high and when you want to write you make the signal on this pin low. For those who are wondering why W has no bar on its top indicating an active low signal, there should be one.

E : This stands for enable. E line is negative edge triggered for write while it is positive edge triggered for the read. The timing diagram given in datasheet tells about the minimum delay between the level transitions.

Now the LCD internal processor takes time to latch and make the necessary adjustments as per the command word. So one should check the status of this flag before sending the next command word or data.

D7 is the busy flag pin. Well you can give delays also for LCD to finish work, but this is better way if you have enough port pins. Using the above table you can make any command byte.

programming lcd in 4 bit and 8 bit mode using 8051

So these are few of the instruction codes that you come across frequently. Of course you can make these on your own by using the command code syntax table. Display data random access memory. This is where the data you send to data register is stored. And it so happens that you can send the address of block to the command code register to position the cursor at that particular block.

For example you want to position the cursor at row 2 column 10just send 0CAh to the command code register. For code explanation watch:.As per the name the 2x16 has 2 lines with 16 chars on each line. Here each character is displayed in a matrix of 5x7 pixels.

Interfacing 16x2 LCD With Msp430 Launchpad in 4 Bit Mode

Apart from alphanumeric chars it also provides the provision to display the custom characters by creating the pattern. Below schematic shows the minimum connection required for interfacing the LCD with the microcontroller.

As we are interfacing the LCD in 4-bit mode, only the higher 4 data lines are used as the data bus. The below configuration is as per the above schematic. First let's see the timing diagram for sending the data and the command signals RS,RW,ENaccordingly, we write the algorithm and finally the code.

The below image shows the timing diagram for sending the data to the LCD. As shown in the timing diagram the data is written after sending the RS and RW signals. It is still ok to send the data before these signals.

The only important thing is the data should be available on the databus before generating the High-to-Low pulse on EN pin. The timings are similar as above only change is that RS is made high for selecting Data register. In the above tutorial, we just discussed how to interface 2x16Lcd in 4-bit mode. For that you need to include the lcd. Download the sample code and design files from this link. Have an opinion, suggestionquestion or feedback about the article let it out here!

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programming lcd in 4 bit and 8 bit mode using 8051

Log in. Interfacing LCD in 4-bit mode with Category : tutorials.Hi dudes…!!! We have already seen lots of tutorials using LCD. If you want see those tutorials please click Here. But here we will see LCD 4 bit interfacing with Microcontroller. Okay can you tell me what is 8 bit mode and 4 bit mode?

Any guess.

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Then why we are going to 4 bit mode? This is the question comes in every mind whenever i said 4 bit mode. Yeah that 8 bit mode is nice. But but but… Just assume.

But have only 32 GPIOs. So in that time i can use this 4 bit mode and reduce the pin required for LCD module.

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Am i right? If we want to enable 4 bit mode we have to do small modification in normal method. In initializing time we have to give 0x28 command. Here everything is same except way of data writing. Here we have only 4 bits. So we need to send nibble by nibble. So first we need to send first nibble then followed by second. See that code.

Because last 4 bits are connected into LCD. RS is connected into P2. RW is connected into P2. EN is connected into P2.

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Hope you learned something from this. If you have any doubt please ask us. See you in next tutorials. This site uses Akismet to reduce spam. Learn how your comment data is processed. Share this:.

Like this: Like Loading Connect with. I allow to create an account.In this instructable I'm writing about 16x2 LCD interfacing with mspg microcontroller. If you don't know about 8 bit mode then I recommend that you read my instructable on 8 bit interfacing.

Now I'm assuming in this instructable that you've already read that part. Need for 4 bit mode Well for interfacing anything with any processor we need system-bus data-bus, address-bus and control-bus.

Thus using these we can control the peripheral that we are interfacing. We are greedy so we want to interface as many peripherals as possible with the same microcontroller. This requires either large number of ports or we need to be smart and utilize what we have to the fullest. Thus first thing is we try to do is reduce the number of pins required for controlling the peripheral.

Here comes the need for 4 bit mode. Thus we reduce the port pins required from 11 to 7. It might not seem much, but for a small microcontroller like mspg with limited port pins this is really a big amount. Now coming to the other method. I got one tip that we can use SIPO shift register for sending data. Now this will require only 5 port pins. Three control pins and two for serial data and clock. For those of you who don't know what a nibble is: a nibble is a group of four bits, so the lower four bits D0-D3 of a byte form the lower nibble while the upper four bits D4-D7 of a byte form the higher nibble.

This enables us to send 8 bit data be it the ASCII code or the command code by using 4 pins instead of 8. The connections remain identical.

The only change is that the lower nibble pins of LCD are unused. Initializing the LCD in 4 bit mode This is perhaps the most tricky part of this interfacing. Using this we form the command code for 4 bit mode operation. Thus the upper nibble of the command code is b which is 0x If we need 2 lines we set N and the normal font so F is 0 thus lower nibble comes out to be b i. Thus total command code is 0x Before sending this 0x28 we need to perform a specific initialization.

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This will do the initial 8 bit mode starting of LCD. Now after this we need to send 0x