Schematic GLCD GDM12864Q with DS89C450 microcontroller.

glcd schematic

Hi all,

I bought this touchscreen GLCD from www.circuit-ed.com.
It is a GDM12864Q (Xiamen Ocular) with Samsung S6B0108 (KS0108)
Controller. I want to interface this GLCD with Maxim Dallas DS89C450
(8051 family - 64KB Flash memory) microcontroller.
I do not know how to connect the GLCD pins (25 pins in SIL) with
microcontroller's pins. Plus, I do not know how to implement the
touch screen by C code (I will be using C Keil Compiler).
I searched google.com for this to no avail. Datasheets provided
by www.circuit-ed.com are not useful. They do not show any
connection at all. I e-mailed www.circuit-ed.com. They do not know
anything about any connection (not even technical support).
What I really need to know is how to connect X-, X+, Y-, Y+ and
R+, G+, and B+ pins to microcontroller. I am just wondering if there
should be any special circuit or chips for making connection between
this GLCD and DS89C450 microcontroller. Any help, guidance, and
URL links would be appreciated.

Have a nice day,
Maximuc54.

glcd initialization

You mean, that the vendor doesn't provide application circuits for the LCD device? But they have basic data sheets of the LCD and some similar resistive touch screens. As you already found out, it's a KS108 compatible graphic display. So what information you're actually missing?

KS108 is common used graphic chip, there are plenty of graphic libraries supporting it. Resistive touchscreen operation is basically simple, but it requires a processor with two ADC channels usually.

4 wire touch screen schematic pic

FvM, thank you for the reply.

Let me elaborate more. I am new to any LCD module
(either characters or graphics based).

I bought this GLCD without knowing the functionalities of
each pin. I got the idea after watching youtube.
It is very cool to interface touchscreen GLCD
with microcontroller (on youtube, it is PIC not MAXIM).

This GLCD has 25 pins (SIL) on the top part and 4-wire
interface on the side.

On the 25-pin part:
Pin #19 is R+;
Pin #20 is G+;
Pin #21 is B+;

Pin #22 is Y-;
Pin #23 is X-;
Pin #24 is Y+;
Pin #25 is X+.

On the 4-wire interface part (transparent cable):
Those 4 wires connected to a socket under the LCD module.

I want to know how to connect the X-, X+, Y-, Y+
and R+, G+, B+ pins (from the 25-pin part) to
microcontroller. I use microcontroller Maxim Dallas
DS89C450 (derivation of 8-bit 8051).

Connection between the LCD module (touchscreen) and
DS89C450 is as follow:
1. Y- (Pin #22) goes to P2.3;
2. X- (Pin #23) goes to P2.2;
3. Y+ (Pin #24) goes to P2.1;
4. X+ (Pin #25) goes to P2.0.

Questions related to touchscreen's functionality:
1. Is this connection correct?
Will the touchscreen functionality work?
2. You mention something about ADC.
From www.circuit-ed.com's youtube, one needs to unplug
these 4-wire and connect them to something.
Do you think this "something" is the ADC chip?
If so then what type of ADC chip and how to connect
it to GLCD and DS89C450?
3. Why there are redundancy ports?
4-wire on the side and 4 pins on the top part?
Do I need to unplug this 4-wire on the side if
I use the 4 pins on the top part?
4. Any source code for testing the touchscreen's
functionality (preferred in C)?

My connection between the RGB pins and DS89C450
is as follow:
1. R+ (Pin #19) goes to P0.5;
2. G+ (Pin #20) goes to P0.6;
3. B+ (Pin #21) goes to P0.7.

Questions related to RGB functionality:
1. Is this connection correct?
2. R+, G+, B+ meaning the GLCD has 3-bit background color?
Examples:
R+ = 1, G+ = 0, B+ = 0 -> Red background
R+ = 0, G+ = 1, B+ = 0 -> Green background
R+ = 0, G+ = 0, B+ = 1 -> Blue background
etc.
Am I correct?
3. Do I need any additional chip to make this RGB work?
4. Any sample code in C for RGB initialization?

Questions related to GLCD initialization:
1. Any flowchart related to this matter?
2. Any sample code written in C for this matter?

The provided datasheets are not sufficient enough
to explain the touchscreen and RGB functionalities.

I want to make a keypad out of this touchscreen
GLCD.

Thank you in advance for any help and guidance.

Have a nice day,
Maxiumuc54.

controller for 4-wire resistive build schematic

In a short, connecting the touchpad (X/Y) and backlight (RGB) terminals to the processors isn't the intended. Only the LCD controller logic pins (1,2,6-17) have to be connected to the processor.

RGB pins are LED terminals, the backlight specifications basically tells how to use it.
The touchpad has to be operated in a two-step sequence, I think: applying a voltage to X, measuring thy Y voltage, then applying a voltage to Y, measuring the X voltage. Perhaps someone, who has designed a touchpanel controller, can guide you. I have no suggestion, which hardware should be supplemented to a pure digital controller, but I'm sure you need something.

I also didn't yet operate a KS0108 graphic controller, may be I once designed a hardware interface, I don't remember every simple design. These chips are similar to some extent, but different in detail.