[General] LCD interfacing with MCU

[Anical]

I was just wondering if all LCD displays require a controller IC. Why can't we directly interface LCD with MCU? Why is a controller IC important?

 

[KlausST]

Hi,

Theoretically you could.

Example:
A "raw" 16 x 4 (Characters x lines) dot matrix glass has
* 16 independent row connections and
* 160 independent column connections.
Makes a total of 176 wires. (in 1:16 MUX)

Have fun soldering it.
Btw. What microcontroller do you decide to connect those 176 wires.

Better read some informations about LCDisplays and related controllers.
like: https://en.wikipedia.org/wiki/Hitachi_HD44780_LCD_controller

Klaus

 

[Anical]

176 wire?! wow thats something. I am using PIC18f4550 and my LCD is mc21605c6w-spr
So I guess I should connect a controller IC between my PIC and LCD other wise 176 wire soldering (haha)
I have noticed that Hitachi HD44780 LCD controller is the most famous.
I came across this where the connection is direct. It got me thinking that if direct connection is possible then how does the controller IC helps us. Anyways what is the criteria to determine a suitable controller for my LCD and MCU. I am not able to find anywhere which can help me.

 

[FvM]

my LCD is mc21605c6w-spr So I guess I should connect a controller IC between my PIC and LCD

mc21605c6w-spr is a regular LCD module with 44780 controller and 4/8 bit parallel interface. What are you actually asking about?

 

[KlausST]

Hi,

I am not able to find anywhere which can help me.

Reading the LCD datasheet should give a lot of answers to your questions.
* It tells you that there already is a controller inside
* It gives you a link to the built in controller datasheet (unfortunately the link doesn´t work with me. But it tells you "SPLC780D" from "SUNPLUS", so it is easy to find.)
(Also you may easily find out that the used controller is (almost) compatible to the famous HD44780)
* it tells you the (number of) connections. You can easily see that it is way below 170.
* It tells you the commands and protocol (A bare LCD glass without controller doesn´t use "commands")


Klaus

(Btw. Your given link is not working for unregistered users)

 

[Anical]

Yes. I bought it because it was cheap with built in controller P). Apparently the controller link and initialization Code link isn't working or its dead. Since it was mentioned that there is controller but nothing else was given or accessible I assumed that I could directly use it with MCU.

Now my question is since the controller is inside the LCD, which connection scheme should I follow?
Based on ICs datasheet I should have IC separately and then connect it with LCD as per given in datasheet whereas LCD datasheet tells that the IC controller is inside. I am quite confused haha

- - - Updated - - -

mc21605c6w-spr is a regular LCD module with 44780 controller and 4/8 bit parallel interface. What are you actually asking about?

Initially I bought it because it had controller inside but when I was looking for tutorials online to check how I can code it to print on LCD they all were using IC controller separately and my LCD datasheet did not mention which IC is being used. It confused me on what to do but now I am getting clearer.

 

[betwixt]

Generally, if the module has 20 or less pins it has an on-board controller.
If it has a much larger number (> 100) it requires direct segment drive from outside. That is still possible and there are MCUs with built in LCD backplane and segment drive circuits but they are relatively rare except in mass produced machines with custom LCD characters.

Brian.

 

[KlausST]

Hi,

There are thousands of documents and threads about how to connect a LCD module to a microcontroller.

It has 14 (maybe 2 additional for backlight) connections. Follow the datasheet´s rules how to connect them.
Then follow the datasheet´s rules how to communicate with it (software)

*****

General hint:
* If you want to use a module, then use the module´s datasheet. (and don´t care what´s inside. Except you want to do something very special)
* if you want to build a circuit with a LCD_controller, then read the LCD_controller´s datasheet. (but this is not what you want to do now)


Klaus