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1  Using Arduino / LEDs and Multiplexing / Re: Small 8x8 matrix driver? on: October 13, 2012, 08:34:04 pm
That part drives nothing at all like an 8x8 matrix.
That part is also thicker than you said your requirement was.

What a waste of time.
No in fact it is thinner then the MAX7219, the SOIC package is only 2mm thick.
Also, I appreciate your answers but no one forces you to answer questions, if you feel its a waste of time, then you shouldn't do it.  No one needs to hear about how you think you've wasted your time on this.
2  Using Arduino / LEDs and Multiplexing / Re: Small 8x8 matrix driver? on: October 13, 2012, 06:53:58 pm
Thanks everyone for your responses, but in the end I will be changing the design around a little so that I can have slightly thicker parts and will be using the AS1130.

Cheers,
Nadav
3  Using Arduino / LEDs and Multiplexing / Re: Small 8x8 matrix driver? on: October 13, 2012, 01:42:12 pm
Gotcha. And yeah i'm still unsure 100% of how im going to go about implementing it...
4  Using Arduino / LEDs and Multiplexing / Re: Small 8x8 matrix driver? on: October 13, 2012, 01:00:13 pm
Still though, shouldn't 115200 baud serial be fast enough for this application?
5  Using Arduino / LEDs and Multiplexing / Re: Small 8x8 matrix driver? on: October 13, 2012, 12:43:07 pm
Another advantage might be interface speed.
MAX7219/7221 can receive data at 10 MHz.  I use  mine at default SPI settings which I think is 4 MHz.
If your main processor was really tied up and you wanted to send stuff out at 8 MHz to get it out of the way quick. The master can do that, I think testing has has shown a 168/328 cannot receive that fast tho due to the slave having to sample (the CS pin?) or something along those lines.
Yeah, ideally that would be the way to go. But size and cost are really the most limiting factor.
6  Using Arduino / LEDs and Multiplexing / Re: Small 8x8 matrix driver? on: October 13, 2012, 12:26:05 pm
It is available on 24-pin wide SO surface mount package - its just a little thicker than you wanted.

Or as bare die if you wanted it really thin.
A bare die would be great, though how would I go about soldering that (or having it soldered for me) in a cost effective and simple way?

Edit: I just did some googling, and it I think the bare die would be overkill for this little production run.
7  Using Arduino / LEDs and Multiplexing / Re: Small 8x8 matrix driver? on: October 13, 2012, 12:19:43 pm
Hmm...good point, though I don't know how reliable they would be in orders of 100. Then again, they might be great. It's too bad they didn't make one of the MAX72xx's in a smaller package...
8  Using Arduino / LEDs and Multiplexing / Re: Small 8x8 matrix driver? on: October 13, 2012, 11:23:06 am
The whole concept of buying max72xx now makes zero sense to me.

Those guys go out of the market for a (very good) reason.

Well there is an advantage to it, especially in very large quantities, and thats the fact that you don't have to program an extra MCU. But yes, cost (and possibly even feature wise) the atmega is the clear way to go.
9  Using Arduino / LEDs and Multiplexing / Re: Small 8x8 matrix driver? on: October 13, 2012, 10:10:54 am
Yep you really cant compare the two in terms of price. If/when I do finish the project, ill be sure to post the code so everyone else can take advantage of the cheaper driver.
10  Using Arduino / LEDs and Multiplexing / Re: Small 8x8 matrix driver? on: October 12, 2012, 03:45:18 pm
Exactly, with the atmega, I can get the for about $3 from digikey, so its really great.
11  Using Arduino / LEDs and Multiplexing / Re: Small 8x8 matrix driver? on: October 12, 2012, 03:20:47 pm
Sweet, its good to know that I can be done! But i'm going to go with the atmega method. Since it is meant to be a production thing (hopefully). And im actually doing a layered pcb assembly à la EEV Blog so its going to be two .8mm pcbs, with a 1.6mm pcb core. The core will have all the places for the ICs and other parts milled out. And the Top and bottom will make it look good, also all of the parts will be on the top pcb. Then ill stick them all together with double sided tape (2mm around the perimeter of the board).
12  Using Arduino / LEDs and Multiplexing / Re: Small 8x8 matrix driver? on: October 12, 2012, 03:07:27 pm
Sweet! That actually makes perfect sense. Now as to how I would do that, would I just do a Serial.write on one end and a Serial.read on the other? and when setting it up I would set Serial.begin to 115200?
13  Using Arduino / LEDs and Multiplexing / Re: Small 8x8 matrix driver? on: October 12, 2012, 03:00:15 pm
Well I figure since its an 8x8 matrix, I would need to transmit 64bit strings of data at a time (maybe a few extra bits to signal a new frame is coming in or things like that)
14  Using Arduino / LEDs and Multiplexing / Re: Small 8x8 matrix driver? on: October 12, 2012, 02:49:40 pm
I'd probably need SPI, though how slow is slow if I wanted to go the serial port route? Also the main atmega, would run at 8MHZ so it wont be super speedy anyways...
15  Using Arduino / LEDs and Multiplexing / Re: Small 8x8 matrix driver? on: October 12, 2012, 02:36:03 pm
Yep something like that, though im still not totally sure exactly how im going to go about it. Like I said, i'm not much of a software guy... Though I think I would need the end product to be something like this https://www.sparkfun.com/products/759 (only much smaller).
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