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Graphic LCD

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electroRF

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Hi,
I got the following GLCD.

In addition to its I2C Ports, it has 4 ROW ports and 4 COLUMNS ports.
However, I did not understand from datasheet what their purpose is.

Is someone familiar with such ports / Keypad? what does it do?

Thanks.
 

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It looks like one graph is obscured a bit, but you can figure it out.

In one of the modes, there is basically 8 buttons connected to pin 9.

In the other mode it's able to deal with a Keypad without much intervention. A key in a typical keypad, connects a row and a column together. So, a 4 x 4 keypad doesn;t require 16 ports. It only requires 8.

The processor is constantly scanning either the rows and and looking for colum transitions or vice versa. A Row, column pair is mapped to each button.

It looks like in the button mode, it's one port per button.

The chip probably enables the pullups correctly.

This **broken link removed** might give you a better idea of what's going on.
 
Hi KISS :)
Thanks
That link you provided is very helpful understanding the mechanism.

This thing is, the LCD came with no buttons.
So, I actually don't have something to press on.
 
Last edited:
user interface, your choice; e,g. **broken link removed** or **broken link removed** or **broken link removed**

Here: **broken link removed** would be a better example using a graphic module

The buttons don't have to be layed out in a matrix, but typically a lot of interfaces use buttons along the edge. Just look at some ATM's where buttons along the left and right edges were used to select functions.

Now I'm spoiled with touch screens.
 
Hi again KISS, thanks.

I can buy one button for the experience.
How shall I connect that button?
I mean, Do I connect it to COL1 / ROW1?
 
On PDF page 14 of the datasheet, the one that's screwed up. You can use X-Y mode. Connected between a row and column

or

You can use button mode. The wire on pin 9 extends through the block. The wires on pins 1 through 8 have a switch in them.
 
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