Interfacing Graphical LCD (ST7920) with Arduino

There are many types of LCDs used in Electronic Projects. We have already used 16X2 LCD in many of our projects and also used TFT LCD with Arduino. You can find our entire 16X2 LCD related project by following this link, including interfacing with 8051, AVR, Arduino and many more.

The ST9720 Graphical LCD is totally different from the Ordinary LCDs. Ordinary LCD can only print simple text or numbers within a fixed size. But in Graphical LCDs we have 128*64 which is equal to 8192 dots or 8192/8 = 1024 pixels, so apart from character, we can display any Graphical Image on this GLCD.

We already interfaced GLCD with 8051, today we will interface Graphical LCD with Arduino to display text and images on it.

Material Required

• Arduino UNO
• 128*64 Graphical LCD ST9720
• Potentiometer-10k
• Connecting wires
• Breadboard

Circuit Diagram

128*64 Graphical LCD

This Graphical LCD is having low power consumption and also suitable for battery power portable device. It have wide operating voltage range 2.2v to 5.5v and supports both serial and 8/4-bit parallel communication and comes with ST7290 LCD controller/driver IC. Interface communication mode can be switched between parallel and serial using PSB PIN 15. This graphical LCD has an automatic power on Reset function and can be easily controlled by MCU such as 8051, AVR, ARM, Arduino and Raspberry Pi.

You can go through with the datasheet for detailed information about ST7290 128*64 Graphical LCD

Pin Configuration

Pin No.	Pin Name	Description
1	Gnd	Ground terminal
2	Vcc	Input supply voltage (2.7v to 5.5v)
3	Vo	LCD contrast
4	RS	Register Select RS = 0: Instruction Register RS = 1: Data Register
5	R/W	Read/Write control
6	E	Enable
7,8,9,10,11,12,13,14	DB0, DB1, DB2, DB3, DB4, DB5, DB6, DB7	Data Pins (used in parallel 8/4bit communication mode)
15	PSB	Interface selection: Low(0) for serial communication mode High (1) for 8/4-bit parallel bus mode.
16	NC	Not connected
17	RST	Reset Pin
18	Vout	LCD voltage doubler output. VOUT ≦ 7V.
19	BLA	Backlight positive supply
20	BLK	Backlight Negative supply

Applications

• Industrial device
• Embedded Systems
• Security
• Medical
• Hand-held equipment

Converting Image into Hex Code:

To show any image on Graphical LCD, we need HEX code of that image, so here are few steps to convert Image into HEX code. Before that you have to make sure that the size of image should not exceed 128*64.

Step-1: Decrease the size of the normal image to 128*64 or less, which you can do using any image editing software like MS paint.

As shown in the picture above, we are setting the width and height of the image to 128*64.

Step-2: Then you need to save the image in “image_name.bmp” format.

Select the format shown in the above image and save the file for further process.

Step-3: After saving it into “.bmp” format you need to convert the image into hex code for printing. For this, I am using the software named GIMP 2, which convert Bmp file to hex code.

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