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Topic: big multiplexing tri colour led cube - will it refresh fast enough ? (Read 3 times) previous topic - next topic

Grumpy_Mike

The propeller is a much more powerful chip than the arduino, for a start the clock speed can be 80MHz compared to the arduino's 16MHz and it has 8 processors inside it as opposed to one. It also has lots more memory.
However it is only 3V3 so not as handy at powering things.
http://en.wikipedia.org/wiki/Parallax_Propeller

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I just realise I should have said in my first post I'm dyslexic

Me too but when I was at school they hadn't invented dyslexia so I was just thick.

magagna

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I was worried that there would be more overhead on the arduino if I ran with more chips ? (if I'm going to struggle with refresh rate)


The fastest way to get bits out of the arduino is the SPI interface; it can pump data out up to 1/2 the system clock. Many of these LED driver chips are basically shift registers so you daisy chain the output from the first to the input of the second -- for example if you have three 8 port chips you just send 24 bits all at once; you don't need to do anything special between chips.

Have you seen the ShiftPWM and ShiftMatrixPWM libraries? They may give you more insight in controlling LED arrays.
http://en.wiktionary.org/wiki/magagna <-- My last name.  Pretty apt.

knighty

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I just realise I should have said in my first post I'm dyslexic

Me too but when I was at school they hadn't invented dyslexia so I was just thick.
[/quote]

same here !

then I went to uni where they tested me and gave me a certificate to say I can't spell

then I got bored and never went back :S


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I was worried that there would be more overhead on the arduino if I ran with more chips ? (if I'm going to struggle with refresh rate)

The fastest way to get bits out of the arduino is the SPI interface; it can pump data out up to 1/2 the system clock. Many of these LED driver chips are basically shift registers so you daisy chain the output from the first to the input of the second -- for example if you have three 8 port chips you just send 24 bits all at once; you don't need to do anything special between chips.
Have you seen the ShiftPWM and ShiftMatrixPWM libraries? They may give you more insight in controlling LED arrays.


thanks, I'll take a look at that :-)

knighty

I've hit a slight snag... getting ready to do the 8x8x8 cube and thought I'd use the same TLC5947DAP I'm planning for the 24x24x24
(to iron out any problems now)


only problem is... they've just arrived... and I wasn't expecting them to be so tiny... and can't find an ic mount thingie for them anywhere... I think I must be looking for the wrong thing...

any ideas anyone ?


I'm kinda stuck here because out of all the people I know... I'm the one who knows about computers electrics... so if I get stuck and can't google / don't know what to google for I'm lost :(


to put it in context here's a photo.....


it's about half as long as my little finger is wide

I guess I'll have to add heat sinks to them too, they're so tiny they won't dissipate heat well,
(I originally thought I'd solder them right into the board which would aid cooling)

Grumpy_Mike


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