Is it possible to use a text lcd as a graphic lcd?


New member
Hello everyone!

I have a question regarding the 634 20x4 LCD. Can you access and set the individual pixels? Basically using the text lcd as a graphical lcd?

I know you can define custom chars but that only allows for 7 chars. I want to be able to set pixels on or off programaticly. Is that possible on your 634 model?

Thanks in advance,

Havoc BMX
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New member
Actually it's eight custom chars and thats per screen. You can turn on/off the pixals for the 6x8 chars any way you want - but you're still limited to arranging these chars defined per screen to make your graphic. It's a physical limitation of the device, not the software coding methods at your disposal.


New member
Could Custom Chars Be Used Like This?

let's say that you had all your 8 chars declared. You output the custom chars.


and they form a graphic. Could you then redeclare 12345678 and output the next line still retaining what you had in the above custom char line on the screen?

- HavocBMX


New member

and thats the problem ... only 8 cchars per screen.

soon as you change the chars for line 2, line 1 is gonna change too.

About the only thing the cust chars are good for is a small logo or bar graphs


New member
But that doesn't make much sense. Especially considering the scrolling ability of the lcd. It scrolls the text by pixel meaning that they must store the image as just that or at some point have a command to turn on and off pixels in the lcd. I'm just wondering how and if I can access those functionalities.

CF Mark

That is a special funtion of the driving IC used on the 632/634.
It still only has 8 custom characters though.