This 16-character, 2-line parallel liquid crystal display achieves a large viewing area in a compact package. It features a yellow-green LED backlight and uses the common HD44780 interface, so sample interface code is widely available for a variety of microcontrollers.
The DDRAM address 0x00 corresponds to the first character of the top line, address 0x0F corresponds to the last character of the top line, address 0x40 corresponds to the first character of the second line, and address 0x4F corresponds to the last character of the second line.
You can find sample HD44780 LCD interface code written for a variety of AVR microcontrollers as part of the Pololu AVR library.
Note that cables and connectors are not included with this display!
|1||Vss||ground (0 V)|
|2||Vdd||5 V logic supply voltage|
|4||RS||H/L register select signal|
|5||R/W||H/L read/write signal|
|6||E||H/L enable signal|
|7-14||DB0 – DB7||H/L data bus for 4- or 8-bit mode|
|15||A (LED+)||backlight anode|
|16||K (LED-)||backlight cathode|
Using Contrast and the Backlight
As shown in the diagram above, a potentiometer whose output is connected to Vo will allow you to set the contrast for optimal viewing of your display.
The backlight in this LCD is composed of LEDs in series. The total voltage drop across these LEDs is typically 4.2 V and the recommended current through the LEDs is 120 mA. You should use a current limiting resistor RLIMIT as shown above where:
RLIMIT = (VBACKLIGHT – 4.2V) / 0.12A
In the diagram above, VBACKLIGHT is shown as 5 V, but you are not restricted to 5 V; any voltage above the diode-drop voltage will work as long as you choose the appropriate value for your current-limiting resistor. You can also use a PWM-controlled MOSFET to achieve variable dimming of the backlight if so desired.
- Size: 85.0 x 29.5 x 13.5 mm
- Viewing area: 64.5 x 16.4 mm
- Dot size: 0.56 x 0.61 mm
- Character Size: 3.00 x 5.23 mm
- Weight 35 g
- Minimum logic voltage: 4.5 V
- Maximum logic voltage: 5.5 V
- Typical LED backlight voltage drop: 4.2 V
- Typical LED backlight current: 120 mA
- Supply current: 2 mA