![]() ![]() A high to low pulse is given at ENpin when data is sent. To send data on the LCD, data is first written to the data pins with R/W = 0 (to specify the write operation) and RS = 1 (to select the data register). Interfacing LCD with Microcontroller – CIRCUIT DIAGRAMĭata lines are connected to Port 2 (P2) LCD Interfacing with 8051 Microcontroller – Programming Send Data In the case of an 8-bit data bus, the lines are referred to as DB0, DB1, DB2, DB3, DB4, DB5, DB6, and DB7. All others are write commands–so RW will almost always be LOW.įinally, the data bus consists of 4 or 8 lines (depending on the mode of operation selected by the user). Only one instruction (“Get LCD status”) is a read command. When RW is high (1), the program is effectively querying (or reading) the LCD. When RW is low (0), the information on the data bus is written to the LCD. The RW line is the “Read/Write” control line. For example, to display the letter “T” on the screen you would set RS high. When RS is high (1), the data being sent is text data which should be displayed on the screen. When RS is low (0), the data is to be treated as a command or special instruction (such as a clear screen, position cursor, etc.). The RS line is the “Register Select” line. 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. 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. The EN line is called “Enable.” This control line is used to tell the LCD that you are sending it data. The three control lines are referred to as EN, RS, and RW. 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). 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). The user may select whether the LCD is to operate with a 4-bit data bus or an 8-bit data bus. The LCD display module requires 3 control lines as well as either 4 or 8 I/O lines for the data bus. Sends data to data pins when a high-to-low pulse is given Low to write to the register High to read from the register ![]() Selects command register when low and data register when high 16×2 LCD Pin DiagramĬontrast adjustment through a variable resistor The data is the ASCII value of the character to be displayed on the LCD. The data register stores the data to be displayed on the LCD. ![]() A command is an instruction given to LCD to do a predefined task like initializing it, clearing its screen, setting the cursor position, controlling the display, etc. The command register stores the command instructions given to the LCD. This LCD has two registers, namely, Command and Data. In this LCD each character is displayed in a 5×7 pixel matrix. The reasons are: LCDs are economical easily programmable have no limitation of displaying special & even custom characters (unlike in seven segments), animations, and so on.Ī 16×2 LCD means it can display 16 characters per line and there are 2 such lines. These modules are preferred over seven segments and other multi-segment LEDs. A 16×2 LCD display is a very basic module and is very commonly used in various devices and circuits. Let us take a look at the working of an LCD. ![]() All of us have seen an LCD, but no one knows the exact working of it. CRT draws more power than LCD and is also bigger and heavier. They have become very common and have taken a giant leap in the screen industry by clearly replacing the use of Cathode Ray Tubes (CRT). We always use devices made up of Liquid Crystal Displays (LCDs) like computers, digital watches, and also DVD and CD players.
0 Comments
Leave a Reply. |
AuthorWrite something about yourself. No need to be fancy, just an overview. ArchivesCategories |