Introduction



The 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 various 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.

For Specs and technical information HD44780 controller Click Here

Pin Description



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 charachers, whereas LCDs supporting more than 80 characters make use of 2 HD44780 controllers.

Most LCDs with 1 controller has 14 Pins and LCDs with 2 controller has 16 Pins (two pins are extra in both for back-light LED connections). Pin description is shown in the table below.


Figure 1: Character LCD type HD44780 Pin diagram


Pin No. Name Description
1VSSPower supply (GND)
2VCCPower supply (+5V)
3VEEContrast adjust
4RS0 = Instruction input
1 = Data input
5R/W0 = Write to LCD module
1 = Read from LCD module
6ENEnable signal
7D0Data bus line 0 (LSB)
8D1Data bus line 1
9D2Data bus line 2
10D3Data bus line 3
11D4Data bus line 4
12D5Data bus line 5
13D6Data bus line 6
14D7Data bus line 7 (MSB)
Table 1: Character LCD pins with 1 Controller
Pin No. Name Description
1D7Data bus line 7 (MSB)
2D6Data bus line 6
3D5Data bus line 5
4D4Data bus line 4
5D3Data bus line 3
6D2Data bus line 2
7D1Data bus line 1
8D0Data bus line 0 (LSB)
9EN1Enable signal for row 0 and 1 (1stcontroller)
10R/W0 = Write to LCD module
1 = Read from LCD module
11RS0 = Instruction input
1 = Data input
12VEEContrast adjust
13VSSPower supply (GND)
14VCCPower supply (+5V)
15EN2Enable signal for row 2 and 3 (2ndcontroller)
16NCNot Connected
Table 2: Character LCD pins with 2 Controller
Usually these days you will find single controller LCD modules are used more in the market. So in the tutorial we will discuss more about the single controller LCD, the operation and everything else is same for the double controller too. Lets take a look at the basic information which is there in every LCD.


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