GLCD: Introduction to Graphical LCD.

There are many types of LCDs flowing in market, and if you feel safe only with 16×2 line LCD than its the time to convert your devices to Graphical LCD.

The Graphical LCD is called graphical because of its pixel nature. The line LCDs only possess the ability to display pixels in rectangular area and pixels are discontinuous. While in GLCD the pixels are spread all over. You can use it to display characters, as well as graphics. And with some programming you can also show bitmap(.bmp) images.

They take data from controller in parallel fashion. Pin configuration are as follows,

DB0-DB7: Data PinsCS1 – CS2: Chip SelectRST: Reset GLCDE: EnableR/W: Read-Write SelectionRS: Register Select

These are the data and control pins which are connected to the processing device such as microcontroller. Other than these are;

VCC: Power InputGND: GroundVO: Contrast Input-Vout: -ve Voltage for ContrastLED+: Backlight +ve Power InputLED-: Ground

Controlling graphical 128×64 LCD based on KS0108

HQM1286404 is pretty old graphical LCD module but it is still popular. This LCD is controlled by KS0108 lcd controller via two segment drivers. LCD backlight color is yellow-green. I think this is good choice for many projects where graphical information needed because of several reasons – you can find libraries around the internet to start working in just a few minutes, also there are several tools that can be used to generate character arrays and graphics.

 Hardest thing for me was to find correct wiring as datasheet I have was for next PCB revision (HQM1286405) as mine are HQM1286404 so dont be mistaken as I did. Here is the correct pin-out of LCD:1 Vcc2 GND3 VCON 4-11 DB0-DB712 CS213 CS114 RESET15 R/W16 D/I17 EN18 Vee out19 LED Anode 20 LED Kathode

You can see that Chip select pins are in reverse order, so if halves of screen are swapped, then you have to swap wires. At VEE pin should be negative voltage near -4.9V. Potentiometer through VCON pin controls LCD contrast. Reset pin can be connected directly to microcontrollers reset circuit. In my case it is separate. Backlight LED can also be adjusted with another potentiometer – is not included here too.