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Basic Electronics » Use 4 digit LED display using fewest possible outputs

August 18, 2010
by weijiajun
weijiajun's Avatar

So I have a project that I would like to be able to use a 4-digit LED display on, something similiar to (http://store01.prostores.com/servlet/oxyelectronics/the-4/7-Segment-LED-DISPLAY/Detail)

I ran into this mc (http://www.austriamicrosystems.com/eng/Products/Lighting-Management/LED-Driver-ICs/AS1108) which looks like it would support the SPI that you use to communicate between micro controllers in your large Marquee sample.

My question is if anyone has any experience with this, and if they have found any pitfalls in it or anything like that.

Thanks

August 19, 2010
by hevans
(NerdKits Staff)

hevans's Avatar

Hi weijiajun,

The chip found should work. You will have to get pretty familiar with the datasheet and figure out what commands to send it to do what you want. I have never worked with one myself, so I can't really tell you how hard it will be. It will at the very least be an interesting adventure.

Have you thought of controlling your 7 segment display using just your microcontroller? By multiplexing over time I think you can drive all 4 digits with 11 pins. 7 for the segments and 4 for the separate digits. You could then have one atmeaga168 dedicated to driving the display that you send data to over the SPI bus. It would be fairly complicated code, and not necessarily less complicated than buying a chip that does the magic for you, but it would be a neat project.

Humberto

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