Data Bus: As shown in the above figure and table, an alpha numeric lcd has a 8-bit data bus referenced as D0-D7. Schematic 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,EN , accordingly we write the algorithm and finally the code. 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.
|Published (Last):||12 September 2016|
|PDF File Size:||8.64 Mb|
|ePub File Size:||16.35 Mb|
|Price:||Free* [*Free Regsitration Required]|
The steps that has to be done for initializing the LCD display is given below and these steps are common for almost all applications. Send 06H for incrementing cursor position. Send 01H for clearing the display and return the cursor. Sending data to the LCD. The steps for sending data to the LCD module is given below. Place data byte on the data register. Pulse E from high to low. Repeat above steps for sending another data.
Circuit diagram. Capacitor C3, resistor R3 and push button switch S1 forms the reset circuitry. Ceramic capacitors C1,C2 and crystal X1 is related to the clock circuitry which produces the system clock frequency. Resistor R1 limits the current through the back light LED and so do the back light intensity.
POT R2 is used for adjusting the contrast of the display. Program for interfacing LCD to microcontroller is shown below. An LCD module can be interfaced with a microcontroller either in 8 bit mode as seen above or in 4 bit mode.
However 4 bit mode uses only 4 data lines along with the control pins. This will saves the number of GPIO pins needed for other purpose. This will save us 4 pins of our controller which we might employ it for other purpose. Here we only need to write to the LCD module. In this way the total number of pins can be reduced to 6. The reset circuit, oscillator circuit and power supply need to be provided for the proper working of the circuit.
As mentioned earlier the 8 bit data is break into two 4 bit data and send to LCD. The necessary commands for the LCD initialization are defined at the end part of the program.
INTERFACING LCD WITH 8051 MIROCONTROLLER with code
The steps that has to be done for initializing the LCD display is given below and these steps are common for almost all applications. Send 06H for incrementing cursor position. Send 01H for clearing the display and return the cursor. Sending data to the LCD. The steps for sending data to the LCD module is given below. Place data byte on the data register.
A Note on Character LCD Displays
Enable signal for row 2 and 3 2ndcontroller Pin no. Its extended capacity is 80 X 8 bits, or 80 characters. The character generator ROM generates 5 x 8 dot or 5 x 10 dot character patterns from 8-bit character codes see Figure 5 and Figure 6 for more details. It can generate 5 x 8 dot character patterns and 32 5 x 10 dot character patterns. Userdefined character patterns are also available by mask-programmed ROM. If user want to display the fourth custom character then the code to display it is 0x03 i.
Arduino LCD Display
Innovation of Engineers