lcd display pic microcontroller for sale

In this tutorial we will see How to Interface a 16×2 character LCD module with PIC 16F877A Microcontroller using MPLAB X IDE and MPLAB XC8 C Compiler. 16×2 Character LCD is a very basic and low cost LCD module which is commonly used in electronic products and projects. 16×2 means it contains 2 rows that can display 16 characters. Its other variants such as 16×1 and 16×4 are also available in the market. In these displays, each character is displayed using 5×8 or 5×10 dot matrix.

For controlling LCD using MPLAB XC8 compiler we need to know the hardware of LCD. These LCDs commonly uses HD44780 compliant controllers. So we need to learn HD44780 Dot Matrix LCD Controller Datasheet. Don’t worry we already developed an LCD library including commonly used functions, so you can use it without any hardware knowledge of LCD.

First two pins GND and VCC (VSS and VDD) are for providing power to LCD display. 3ed pin VEE is used to control the contrast of the LCD display. A 10KΩ preset whose fixed ends connected to VDD, VSS and variable end connected to VEE can be used to control contrast of the LCD. A microcontroller or microprocessor need to send 2 types of information for operating this LCD Module, Data Information and Command Information. Data Information is the ASCII value of the characters to be displayed in the LCD screen and Command Information determines other operations such as position to be displayed, clear screen, shift etc. Data and Command Information are send to LCD through same data lines (DB0 – DB7) which are multiplexed using RS (Register Select) pin of LCD. When RS is HIGH LCD treats DB0 – DB7 data pins information as Data to be displayed and when it is LOW LCD treats it as Command Information. Enable (E) input of the LCD is used to give Data Strobe. HIGH (5V) Voltage Level in the Enable (E) pin tells the LCD that DB0 – DB7 contains valid information. The input signal R/W (Read or Write) determines whether data is written to or read from the LCD. In normal cases we need only writing hence it is tied to GROUND in circuit shown below.

The interface between this LCD and Microcontroller can be 8 bit or 4 bit and the difference between them is in how the data or commands are send to LCD. In the 8 bit mode, 8 bit data and commands are send through the data lines DB0 – DB7 and data strobe is given through E input of the LCD. But 4 bit mode uses only 4 data lines. In this 8 bit data and commands are splitted into 2 parts (4 bits each) and are sent sequentially through data lines DB4 – DB7 with its own data strobe through E input. The idea of 4 bit communication is introduced to save pins of a microcontroller. You may think that 4 bit mode will be slower than 8 bit. But the speed difference is only minimal. As LCDs are slow speed devices, the tiny speed difference between these modes is not significant. Just remember that microcontroller is operating at high speed in the range of MHz and we are viewing LCD with our eyes. Due to Persistence of Vision of our eyes we will not even feel the speed difference.

Hope that you got rough idea about how this LCD Module works. Actually you need to read the datasheet of HD44780 LCD driver used in this LCD Module to write a MPLAB XC8 program for PIC. But we solved this problem by creating a header file lcd.h which includes all the commonly used functions using 4 bit mode. Just include it and enjoy.

Lcd_Set_Cursor(int row, int column) : This function is used to set row and column of the cursor on the LCD screen. By using this function we can change the position of the character or string displayed by following functions.

sprintf() can be used to write formatted string to a variable. It can be used with this LCD library to format displayed texts. This enables us to display integers and floating point numbers on the LCD very easily. You should include the header file stdio.h for using sprintf().

Using the serial enabled controller, it is easy to connect to any microcontroller that has a serial UART port such as an Arduino, AVR, PIC, etc. The SerLCD supports 16 and 20 character-wide screens with 2 or 4 lines of display.

Depending on your LCD"s specs, the input voltage may be 3.3V or 5V. For the LCDs listed below, the input voltage for the backpack must be 3.3V even though the silkscreen says 5V. The logic levels will be the same as the input voltage.

The LCDs listed below require an input voltage of 5V. Higher than 5.5V will cause damage to the PIC, LCD, and backlight (if attached). At 5V, the SerLCD uses 3mA with the backlight turned off and ~60mA with the backlight activated. The following LCDs do not have a SerLCD backpack.

The SerLCD and built-in serial LCDs comes equipped with a 10k potentiometer to control the contrast of the LCD. This is set during assembly and testing but may need correcting for your specific LCD module. Temperature and supply voltage can affect the contrast of the LCD. While powered, simply adjust the potentiometer with a screw driver.

The SerLCD v2.5 uses a general purpose, 1000mA NPN transistor to control the LCDs backlight. If you purchased the SerLCD module, you may use this pin as a general purpose, high power control pin. If you issue the backlight on/off command to the SerLCD or built-in serial LCD, the BL pin on the board can also be used to power / control other circuits with a maximum current of 1000 mA. This is usually the last pin on the top row of the LCD. Check your datasheet for proper pin outs.

In this tutorial, we’ll discuss how Alphanumeric LCD works and how to interface a 16×2 LCD with a microcontroller. You’ll learn how LCD (Liquid Crystal Display) works internally and how to send data and commands to it with a microcontroller, specifically PIC MCUs. And you’ll also learn how to develop a simple LCD Driver for your upcoming projects.

We typically add a 16×2 Alphanumeric LCD to small embedded systems & projects to enhance the user experience and UI of the device/project. You can use it to display text messages to the user, number, etc. Other types of LCDs provide different features such as the number of columns and rows (characters) and maybe colored display, and also different interfaces (parallel, spi, i2c, etc).

For this tutorial, we’ll consider the 16×2 LCD with a 16-pin header interface. Assuming it has the standard Hitachi LCD driver HD44780 controller. We’ll see how it works internally and how to interface it with microcontrollers. This small IC on the backside of the LCD module controls the LCD itself and accepts user commands and data sent by the master MCU.

The LCD module consists of 16×2 character cells, and each one of them is 5×8 dots. Controlling all of this is a tedious task for our main microcontroller to do. However, it doesn’t have to do. As there is a specific function controller on the LCD itself controlling the display while reading in the user’s commands & data. Here, I’ll be considering the Hitachi HD44780 controller.

The HD44780U has two 8-bit registers, an instruction register (IR) and a data register (DR). The IR stores instruction codes, such as display clear and cursor shift, and address information for display data RAM (DDRAM) and character generator RAM (CGRAM). The IR can only be written from the MPU. The DR temporarily stores data to be written into DDRAM or CGRAM and temporarily stores data to be read from DDRAM or CGRAM. Data written into the DR from the MPU is automatically written into DDRAM or CGRAM by an internal operation.

Display data RAM (DDRAM) stores display data represented in 8-bit character codes. Its extended capacity is 80 × 8 bits, or 80 characters. The area in display data RAM (DDRAM) that is not used for display can be used as general data RAM. Therefore, whatever data you send to the DDRAM, it’ll get displayed on the LCD. As long as the characters count is below 32 (for 16×2 LCD), it’ll be visible. Otherwise, written characters are stored in the DDRAM but not visible.

The table down below shows you the standard ASCII equivalent characters for the LCD display stored in the CGROM. And you can also create your custom characters and symbols if you want to, as we’ll see in a future tutorial. Note the “A” character which has a binary code of (0100 0001)b this is equivalent to 65 (the ASCII value for A in the ASCII table).

The cursor/blink control circuit generates the cursor or character blinking. The cursor or the blinking will appear with the digit located at the display data RAM (DDRAM) address set in the address counter (AC).

There are two ways to interface the LCD diver (controller) IC. You can use the full bus width (8-Bits) for data or alternatively you can use a 4-Bit interface for a reduced pin count needed to control the LCD. Specifically low pin count MCUs need to operate in the 4-Bit mode.

At the beginning of your system’s firmware, you should do some initialization steps for the LCD display before it’s usable. These steps are listed by the manufacturer of the LCD Driver IC and let your LCD know how it’s going to operate afterward. Which interface mode you’ll be using (4 or 8 bits), which font and so on.

The LCD takes some time to process commands or data. Therefore, there must be a small delay before issuing a new command to the LCD. This delay could be chosen arbitrarily as long as it’s longer than the time required by the LCD itself as indicated in the datasheet. Alternatively, you can just read the busy flag bit to know whether the previous command was successfully processed or not.

When a data or a command is sent to the LCD, the BF or D7 bit of the LCD becomes 1 and as soon as the command is successfully processed, the BF becomes 0.

First of all, we should define the IO pins which we’ll be using to interface the LCD. It’s a recommended practice to isolate the hardware drivers firmware from the application layer and for the sake of portability of your code. This step makes your code less dependent on the specific MCU chip you’re using in the current project.

We’ll be using the 4-Bit interface in these tutorials as it’s the most common and most wished for. Nobody wants to consume all of his microcontroller’s pins just to hook an LCD. In fact, there is an I2C interface for the LCD which we’ll be using in a future tutorial and its main feature is reducing the pin count used for LCD control.

All in all, what we need now is a routine to parse out half-a-byte of data and send these bits to the corresponding pins of the IO pins associated with LCD Data. Here is a simple implementation for such a routine.

As we’ve discussed earlier in this tutorial, sending a command to the LCD should start with selecting the command register. Then the command data is transferred to the LCD io data pins. Then we should clock or send enable signal pulse. This routine is followed in general settings, whether it’s a 4-Bit interface of an 8-Bit.

Now, it’s time to create the LCD initialization routine. This function is an exact implementation of the steps we’ve discussed earlier in this tutorial. The 4-Bit interface initialization steps are indicated in a previous flow chart and our task right now is to implement it in C.

Sending an 8-Bit character to the LCD followed by an enable pulse (clock) will display that character on the LCD. However, in our case of using a 4-Bit interface, this step will be divided into two consequent steps. First of which is parsing the 8-Bit character into a high_nibble and low_nibble. Then we’ll send the high4 bits first followed by an EN clock, then we’ll send the low4 bits followed by another EN clock. And that’s it!

To send a string to the LCD, we’ll need a loop to repeatedly send characters to the LCD until a buffer end is found, and typically it’s the NULL character “\0”. Here is the implementation of this routine.

As you’ve seen in the previous sections, the datasheet of the LCD driver IC includes all the command that it could handle. And we’re going to add a couple of them to our LCD Driver code. All the rest are left for you to experiment with. Some specific commands may help you in specific projects and it’s up to you to decide on which one you need to implement.

The header file includes only the declarations of sub-routines with simple documentation indicating the functionality of each routine and what it takes and returns if it’s not void, etc. The LCD.h header file will be something like this

It’s now way more clean/clear. And it’s easier to debug or extend the functionality of your LCD driver module. Here is the compiled project, download it and customize it as you wish.

Open the MPLAB IDE and create a new project name it “LCD_16x2_LAB1”. If you have some issues doing so, you can always refer to the previous tutorial using the link below.

Open the MPLAB IDE and create a new project name it “LCD_16x2_LAB2”. If you have some issues doing so, you can always refer to the previous tutorial using the link below.

In this tutorial, we’ve implemented some of the most common LCD commands that you are most likely to use in your various projects. However, there still are some other commands that you can implement and test on your own. Just get the datasheet and start tinkering around and if you feel stuck at any point, just drop me a comment and I’ll be here to help you.

As we’ve discussed in a previous section, it’s a recommended practice to separate your device drivers layer from the application layer as much as possible. It helps in terms of portability and enhances code re-usability. Each device driver should have a header file .h and a source file .c and you can #include this library in whichever project you want. Reducing the time to port your project to another platform (microcontroller).

You can use the sprintf function from the standard library by including stdio.h. Now you can combine numbers (int, float, etc) with text in a single array “string” that you can print out on your LCD. We’ve done this in a previous lab for the LM35 sensor.

LCD stands for Liquid Crystal Display. An LCD is a passive device. It does not produce any light and simply alters the light travelling through it. With a voltage applied to it, the liquid crystal polarizes transmitted light in a different direction to when no voltage is applied. A polarizing filter in front of the display then blocks one of the two polarizations (i.e. the areas in which a voltage was applied or the ones where no voltage was applied) and therefore in some areas of the screen appear ‘black’, this effect is used to draw the characters and graphics displayed by an LCD.

2. Glass substrate with ITO electrodes. The shapes of these electrodes will determine the shapes that will appear when the LCD is turned ON. Vertical ridges etched on the surface are smooth.

Almost all LCDs have a strong light source built in behind a glass panel (which contains the liquid crystal), this ensures that the areas of light and dark on the screen (dictated by the areas on the liquid crystal panel across which a voltage is applied) have good contrast. Displays with no backlights that rely solely on the light incident on the LCD panel cannot be used in low light conditions.

Most commonly used character based LCDs are based on Hitachi’s HD44780 controller or other which are compatible with HD44580. In this tutorial, we will discuss about character based LCDs, their interfacing with PIC microcontrollers, various interfaces (8-bit/4-bit), programming, special stuff and tricks you can do with these simple looking LCDs which can give a new look to your application.

The most commonly used LCDs found in the market today are 1 Line, 2 Line or 4 Line LCDs which have only 1 controller and support at most of 80 characters, whereas LCDs supporting more than 80 characters make use of 2 HD44780 controllers.

Most LCDs with one controller have 14 pins or 16 pins (two extra pins are for back-light LED connections) while LCDs with two controllers have two more pins to enable the additional controller. We will focus on LCDs with one controller in this article since it is one of the commonly used models in the market. Likewise, the operations are applicable for two controllers LCD as well. Pin description is shown in the table below.

The HD44780 standard requires 3 control lines as well as either 4 or 8 I/O lines for the data bus. The user may select whether the LCD is to operate with a 4-bit data bus or an 8-bit data bus. If a 4-bit data bus is used the LCD will require a total of 7 data lines (3 control lines plus the 4 lines for the data bus). If an 8-bit data bus is used the LCD will require a total of 11 data lines (3 control lines plus the 8 lines for the data bus).

The EN line is called “Enable.” This control line is used to tell the LCD that you are sending in data. To send data to the LCD, your program should make sure this line is low (0) and then set the other two control lines and/or put data on the data bus. When the other lines are completely ready, bring EN high (1) and wait for the minimum amount of time required by the LCD datasheet (this varies from LCD to LCD), and end by bringing it low (0) again.

The RS line is the “Register Select” line. When RS is low (0), the data is to be treated as a command or special instruction (such as clear screen, position cursor, etc.). When RS is high (1), the data being sent is text data which sould be displayed on the screen. For example, to display the letter “T” on the screen you would set RS high.

The RW line is the “Read/Write” control line. When RW is low (0), the information on the data bus is being written to the LCD. When RW is high (1), the program is effectively querying (or reading) the LCD. Only one instruction (“Get LCD status”) is a read command. All others are write commands–so RW will almost always be low.

Finally, the power supply pins for the backlight – LED+ and LED-. Some LCD modules come without the backlight. In that case, these pins are not found or are left disconnected. The recommended voltage for LED+ is 4.2V and LED- should be connected to ground (GND). Vary the value of the resistor connected to LED+ will change the brightness of the backlight. Normally, 220 Ohm or 330 Ohm resistor will be used. For advanced user, you may connect the pin to PWM output and change the brightness in your software by altering the PWM duty cycle. We will further discuss this in upcoming issues.

A typical LCD hardware connection to PIC microcontroller with backlight turned on permanently is shown in figure below. To turn off the backlight, disconnect the supplies to pin 15 and 16. RB4, RB5 and RB6 of PIC16F877A are used for the control signals while PORTD of the microcontroller is the data bus.

Display data RAM (DDRAM) stores display data represented in 8-bit character codes. Its extended capacity is 80 X 8 bits, or 80 characters. The area in display data RAM (DDRAM) that is not used for display can be used as general data RAM. So whatever you send on the DDRAM is actually displayed on the LCD. For LCDs like 1×16, only 16 characters are visible, so whatever you write after 16 characters is written in DDRAM but is not visible to the user. Figures below will show you the DDRAM addresses of 1 line and 2 lines LCDs.

Now you might be thinking that when you send an ASCII value to DDRAM, how the character is displayed on LCD? So the answer is in CGROM. The Character Generator ROM (CGROM) generates 5×8 dots or 5×10 dots character patterns from 8-bit character codes (see figures below for more details). It can generate 208 5×8 dot character patterns and 32 5×10 dot character patterns. User-defined character patterns are also available by mask-programmed ROM. Here we will only discuss 5×8 dots character patterns LCD module which is commonly used.

As you can see in both the code maps, the character code from 0x00 to 0x07 is occupied by the CGRAM characters or the user defined characters. If user wants to display the fourth custom character then the code to display it is 0x03 i.e. when user sends 0x03 code to the LCD DDRAM, the fourth user created character or pattern will be displayed on the LCD.

As indicated by its name, CGRAM area is used to create custom characters in LCD. In the character generator RAM, user can rewrite character patterns by program. For 5 x 8 dots, eight character patterns can be written, and for 5 x 10 dots, four character patterns can be written. We will not cover how to use CGRAM area to make custom characters in this tutorial. Please stay tune for the future issue.

Busy Flag is a status indicator flag for LCD. When we send a command or data to the LCD for processing, this flag is set (i.e BF =1) and as soon as the instruction is executed successfully this flag is cleared (BF = 0). This is helpful in determining the exact amount of delay for the LCD process.

To read Busy Flag, the condition RS = 0 and R/W = 1 must be met and the MSB of the LCD data bus (D7) acts as busy flag. When BF = 1 means LCD is busy and will not accept next command or data and BF = 0 means LCD is ready for the next command or data to process.

There are two 8-bit registers in HD44780 controller Instruction and Data register. Instruction register corresponds to the register where you send commands to LCD e.g LCD shift command, LCD clear, LCD address etc. and Data register is used for storing data which is to be displayed on LCD. When send the enable signal of the LCD is asserted, the data on the pins is latched in to the data register and data is then moved automatically to the DDRAM and hence is displayed on the LCD. Data Register is not only used for sending data to DDRAM but also for CGRAM, the address where you want to send the data, is decided by the instruction you send to LCD. We will discuss more on LCD instruction set further in this tutorial.

Only the Instruction Register (IR) and the Data Register (DR) of the LCD can be controlled by the MCU. Before starting the internal operation of the LCD, control information is temporarily stored into these registers to allow interfacing with various MCUs, which operate at different speeds, or various peripheral control devices. The internal operation of the LCD is determined by signals sent from the MCU. These signals, which include register selection signal (RS), read/write signal (R/W), and the data bus (DB0 to DB7), make up the LCD instructions. There are four categories of instructions:

Although looking at the table you can make your own commands and test them. Below is a brief list of useful commands which are frequently used while working on the LCD.

The table above will help you while writing programs for LCD. But after you are done testing with it, I recommend you to use the previous table (Commands and Instructions set for LCD type HD44780) to get more grip on working with LCD and trying your own commands.

That’s all for this issue. In the next part of the tutorial we will continue with the software programming for PIC microcontrollers to interface with the LCD module. Please continue to follow this topic and let your application interacts with you through LCD!

TV mounts provide consumers and businesses alike with stylish and easy-to-install options for monitor placement. Instantly transform a small space into a home theater or a modern and minimalist living room by adding a retractable pic microcontroller lcd or wall mount. These pieces of hardware provide a supportive, practical, and versatile piece of equipment to any home and the best part is they"re virtually invisible to the naked eye.

Flat-screen TVs opened new doors to innovative TV brackets and mounting displays many years ago. Today, standing TV mounts, ceiling TV mounts, and corner TV mounts are all great options for consumers who are looking to save space and add a modern touch to their environment. Full motion TV wall mounts and swivel mounts can provide anywhere from 45-degree to 360-degree motion for the ultimate viewing experience. Outdoor TV mounts and projector mounts are also convenient for outdoor events all year round. Browse a range of different material types on Alibaba.com to find everything from lightweight aluminum to heavy-duty steel pic microcontroller lcd depending on your customers" preferences and requirements.

In this project i am going to interface 16×2 lcd display in 4-bit mode with Microchip Pic16f877 microcontroller. We can interface any size of character lcd display (8×1,8×2,10×1,10×2, 16×2,16×2,16×4,20×1,20×2,40×1,40×2 etc) in 4-bit mode with pic microcontrollers. In 4-bit interface mode only 4 lcd data lines are used to display data on lcd screen. Usually lcd is interfaced in 4-bit mode with microcontrollers to save I\O pins of microcontrollers. Before beginning any further i assume that you know difference between 4-bit and 8-bit lcd interfacing mode with microcntrollers. If not just take the below simple tutorial. Tutorial will help you in understating the basic difference, pros and cons of both the modes. It will also help you in understanding the code below easily.

In 4-bit mode only 4-bit data is send to lcd at a time. Since 8-bit microcontrollers contains data in 8-bit form so we divide our data in to two nibbles(1-nibble=4-bits). First higher 4-bits(nibble) is send to lcd and then the lower 4-bits(nibble) with enable stroke signal. Only D4,D5,D6,D7 data pins of 16×2 lcd are used in 4-bit interface mode. D1,D2,D3,D4 are left empty. D4 is our least significant bit and D7 is highest significant bit in 4-bit interface mode. A typical interfacing diagram is given at the right side.

Interfacing 16×2 lcd with Pic16f877 microcontroller is simple, if you have taken the above tutorial. The circuit of the project is also very simple. Port-B first 4 bits (RB0,RB1,RB2,RB3) of Pic16f877 microcontroller are used to send 4-bit data and commands to lcd. These four Pins(RB0,RB1,RB2,RB3) are Connected to four data pins of 16×2 lcd(D4,D5,D6,D7).Port-D pin# 5 is connected to rw(read-write) pin of lcd. Port-D pin# 6 is connected to rs(register select) pin of lcd. Port-D pin# 7 is connected to en(Enable) pin of 16×2 lcd. If you are newbie and have to idea about the working and pin configuration of lcd. Below is a good tutorial.

This function is separating four bits from our command and puts them on RB0,RB1,RB2,RB3 line and then sends them to lcd. The following instructions are separating four bits.

This function is separating four bits from our 8-bit data and puts the 4-bit data on RB0,RB1,RB2,RB3 pins and then sends them to lcd. Following instructions are separating four bits.

In the main function i first called lcdint() function. This function is initializing our lcd. Refer to the data sheet of lcd if you dont know what is lcd initialization. Then i am sending data to 16×2 lcd which i want to display on lcd screen. I am displaying word “Microcontroller” on lcd display screen.