The GLCD (Graphics LCD) display that I’ll be using in this series is the JHD12864E. Here’s a picture of what it looks like (image stolen from http://extremeelectronics.co.in):
It’s a fairly standard 128×64 pixels display with a backlight. The part number aside, what really matters is the IC driver that is used in this display. The datasheet shows (more on this in a few mins) that it uses the S6B0108 display driver. After looking around on the net, I realised that this is similar to the KS0108 family display driver. So the general method of operation should be similar to the KS0108 but with a few minor differences here and there.
The reason I’m explaining this is because you can use any KS0108 based display and follow along and should be able to get it to work. There’s no need to search for the JHD12864E that I’m using.
Now, let’s spend a few minutes talking about the datasheet. Every time you get a new electronic component, your first step should be to look for the datasheet. In this case, here’s the link to the datasheet for the JHD12864E.
The first thing that hits you when you open the datasheet is that there are more pages with weird cartoons that show what weather your device can survive in than pages explaining how to use the damned device! Never fear, that’s why this series is here!
However, there are two things in the datasheet that are very important. The instruction set and the pin configuration/interface. While searching on the net, I realised there are quite a few variations of these so you should make sure that you’re referring to the datasheet of your own device when working with this. Here’s a quick copy paste of what’s there in my sheet:
Here are some things you should look for in your datasheet:
1. Chip selection – do I select the chip by putting the pin to High (1) or to Low(0)? We’ll cover more about Chip selection in a later part
2. Pin configuration – VCC (+5V) and GND are sometimes interchanged. Make sure you don’t connect them in reverse
In the next part, we’ll understand how the screen resolution works and how we can address a particular pixel on the screen