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46  Using Arduino / LEDs and Multiplexing / Re: Scrolling text on LED matrices using SPI and arduino Mega2560 on: November 06, 2012, 11:47:49 pm
Thanks for clearing up the sequence layout.:you have been so helpful.....I'm a junior engineer with a good yr. Arduino time......just wanting this to be right....ill upload in the morning once I do the caps better....need to find some 104's
47  Using Arduino / LEDs and Multiplexing / Re: Scrolling text on LED matrices using SPI and arduino Mega2560 on: November 06, 2012, 10:24:53 pm
is there anyway you could take the code I pasted before and update it with your updates and repost it.....I'm starting to lose track of everything...I'd appreciate it....


Also one thing I need to be certain of.....

imagine you have your 4 matrices  going from left to right with each having the max7219 under them.....

the first max7219 that needs to be interfaced from the arduino is farthest to the right then going from right to left correct? Or is it farthest to the left going to the right.....

I know I'm blowing up these forums...I just want to get this right....

48  Using Arduino / LEDs and Multiplexing / Re: 8 x 32 display on: November 06, 2012, 10:20:04 pm
crossroads,

I'm looking at your block diagram in this forum and if I'm interpreting it correctly, you dont have the data pins in parallel...you have the data out pin on each max7219 interfacing the next chips data in pin...Thats what I was trying to say about the website on the playground earlier......

Then I don't get the ss0-ss3 now...

I'm about to scrap the mega2560 for this and try it with an Uno or Duelminove....
49  Using Arduino / LEDs and Multiplexing / Re: max7219 expert needed 8x64 matrix on: November 06, 2012, 08:16:28 pm
What version of arduino IDE are you using with this code...I have 1.0.1 and its sayinmg error due to the ledcontrol.....
50  Using Arduino / LEDs and Multiplexing / Re: Scrolling text on LED matrices using SPI and arduino Mega2560 on: November 06, 2012, 07:43:49 pm
Now I'm getting conused again......

this is taken from the playground website:

"If you read the datasheet for the MAX72XX you know that the drivers can be cascaded by simply connecting the signal DOut from one chip to DIn on the next chip. The signals Clk and Load(/CS) have to be connected  in parallel to each MAX72XX. There is no strict limit as to how many drivers can be cascaded that way."

I don't have the Loads connected in parallel...they are set up from ss0-ss3 individually from the arduino I/Os  53, 49, 48 and 47......
51  Using Arduino / LEDs and Multiplexing / Re: Scrolling text on LED matrices using SPI and arduino Mega2560 on: November 06, 2012, 07:35:42 pm
Taken from the Playground site we are mentioning here...I have it in my posting about the scrolling on matrices.....


"By no means these 2 capacitors can be ommitted (Left out), as it might lead to sporadic or permanent malfunctions. These types of errors are really hard to track down. Both capacitors must be placed as near as possible to the V+ and the Gnd pins of the MAX72XX. "


I need to re place the caps closer.....and not just on Vcc and ground planes.....
52  Using Arduino / LEDs and Multiplexing / Re: MAX7219 in daisy chain. How many decop capacitors I need? on: November 06, 2012, 07:34:57 pm
Taken from the Playground site we are mentioning here...I have it in my posting about the scrolling on matrices.....


"By no means these 2 capacitors can be ommitted (Left out), as it might lead to sporadic or permanent malfunctions. These types of errors are really hard to track down. Both capacitors must be placed as near as possible to the V+ and the Gnd pins of the MAX72XX. "


I need to re place the caps closer.....and not just on Vcc and ground planes.....
53  Using Arduino / LEDs and Multiplexing / Re: Scrolling text on LED matrices using SPI and arduino Mega2560 on: November 06, 2012, 07:29:05 pm
I noticed and commented in the similar post going on about the coupling caps......It was mentioned to use a 10 uF polarized cap and no less than a 0.1 uF ceramic cap for each device....I'll change up the caps tomorrow because I know I didn't use the correct ceramic caps.....I think I used 0.001 uF
54  Using Arduino / LEDs and Multiplexing / Re: MAX7219 in daisy chain. How many decop capacitors I need? on: November 06, 2012, 07:22:57 pm
Riva ****** I'm sorry about that.....I said Rita before
55  Using Arduino / LEDs and Multiplexing / Re: MAX7219 in daisy chain. How many decop capacitors I need? on: November 06, 2012, 07:22:09 pm
Like Rita said....

I'm with Crossroads in both caps per chip but minimum should be a 0.1uF per chip and maybe 10uF a pair.


I'm going to need to redo the caps I have.....

check out my WIP

56  Using Arduino / LEDs and Multiplexing / Re: Scrolling text on LED matrices using SPI and arduino Mega2560 on: November 06, 2012, 07:19:02 pm
I have recorded a video of what I have so far.....

I was thinking I may need to do a better job with the caps......

I may resolder them in from each Vcc on the max7219s to its ground and not just on a Vcc / Gnd plane......that run parallel ya know on the PCB (Radio shack board)

anyways, heres the video..



I bought 10 more max7219s tonight as well...10  for 4.99 $ can't beat that......

If I can't get this to work, I may just go with the Uno / Duelminove and use an i2c LCD to conserve the I/Os but then redesign the enclosure as well....


anyhows....Still WIP but I'm trying
57  Using Arduino / LEDs and Multiplexing / Re: MAX7219 in daisy chain. How many decop capacitors I need? on: November 06, 2012, 04:58:14 pm
Schematic n code?
58  Using Arduino / LEDs and Multiplexing / Re: Scrolling text on LED matrices using SPI and arduino Mega2560 on: November 06, 2012, 04:24:38 pm
I'm not 100 % sure where you would add this in.....so I took a guess....

attached is my entire code so far....

the schematic and picture is posted...I replaced resistors with 33 K's now instead of 10 K's....

I have an electrolytic 10 uF cap on each device and a .01 u F ceramic cap on each (I was hoping that could work)

disregard the email tonight.....

I'm going to take a video tonight of it working so far.....so you'll have a better image...

attached is the code so far....with a few updates you gave me....
59  Using Arduino / LEDs and Multiplexing / Re: Scrolling text on LED matrices using SPI and arduino Mega2560 on: November 06, 2012, 03:53:36 pm
Why thank you...I made the enclosure with a Vernier Caliper, A dremmel and a file.......took a few days...I bought the 40 x 2 LCD for 2.75 $ and wanted to something with it right....

I then bought a mega and I wanted to have multiple things working on the enclosure....so I made the matrices as well.....

I updating the code now....

I did add the caps....now I can get some type of response from the 3rd and 4th matrix...at least I'm getting there now....

When I power up, its like the first whole matrix is lit, the 2nd row of the 2nd matrix is lit and then all of 3rd and 4th matrices are lit.....

When I open the serial monitor, the LCD resets and goes through the setup again......

getting there.....Arduino is so much fun.....debugging and all...
60  Using Arduino / LEDs and Multiplexing / Re: Scrolling text on LED matrices using SPI and arduino Mega2560 on: November 06, 2012, 02:50:15 pm
Attached is a picture of my project is you're curious.....

Everything works how I would like it to except the matrices.....They are blinking erratically at times...or steady on....etc.
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