32x16 LED Matrix Color

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us682112
 
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32x16 LED Matrix Color

Post by us682112 »

I've got my 32x16 LED matrix lit up using an Arduino Mega. I'm using a "Medium 16x32 RGB LED matrix panel - 6mm Pitch PID: 420" and Adafruit RGB Matrix Shield for Arduino PID: 2601 to wire it to the Mega. I'm just using the provided ribbon cable to connect shield to matrix.
Running the testcolors _6x32 sample, the color is close, but not right - please see attached pic with first 8 rows x 32.
Could this be due to wiring? I've checked it, but I'm also new at this. Thanks.

Rick
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Re: 32x16 LED Matrix Color

Post by adafruit_support_carter »

It could be a connection issue of some kind. Please remove the shield from the Mega and disconnect the ribbon cable. Post some photos of both sides of the shield showing the soldering job on the shield header pins and ribbon connector pins.

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Re: 32x16 LED Matrix Color

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Here they are attached. I oriented the header pins up with the ribbon cable - seemed to make it easier to connect. Thanks.

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Re: 32x16 LED Matrix Color

Post by adafruit_support_carter »

Thanks. That soldering looks good.

The outer header pins are not solder on though. How is the shield being attached to the Mega?

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Re: 32x16 LED Matrix Color

Post by us682112 »

Jumpers - I didn’t think the headers lined up based on documentation, so didn’t even try. I’ve got 12 individual signals and the four grounds soldered to a leader terminating on the Mega.

Rick

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Re: 32x16 LED Matrix Color

Post by adafruit_support_carter »

The Mega can accept standard Arduino shields. It's larger than an UNO, but has a common form factor on the initial set of pins. Try soldering on the main headers so the shield can be directly attached to the Mega:
https://learn.adafruit.com/32x16-32x32- ... rix-shield

Connecting with jumper wires if very problematic and not supported:
https://learn.adafruit.com/32x16-32x32- ... mper-wires

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Re: 32x16 LED Matrix Color

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Well huh, I read this:
"The shield does not directly work with the Arduino Mega — additional jumper wires are needed to pins off the shield — see the “Jumper Wires” page for pinouts, or consider making your own Mega proto shield for that board.",
and thought jumpers (or something). But the attached picture shows you're right. I haven't soldered them yet, but will this weekend and see if that takes care of the issue. Thanks.

Rick
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Re: 32x16 LED Matrix Color

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I've not had time to finish the soldering - hopefully in the next couple of weeks. I'm running out of time on the skee ball project, so I ended up using the Adafruit 1.2" 4 digit 7 segment display for the score -https://www.adafruit.com/product/1270. During this process, I discovered the "good" 5v 2A power supply I had for the matrix, wasn't putting out the voltage (amps? I'm a noob). But, now I'm thinking that wasn't helping my color situation either - could that be a cause as well? Thanks for the help - really appreciate it.

Rick

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Re: 32x16 LED Matrix Color

Post by adafruit_support_carter »

A flakey power supply could definitely cause issues. What were you seeing that makes you think it's not delivering the rated voltage and current?

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Re: 32x16 LED Matrix Color

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Sorry for delay, but it wouldn’t power the 7 segment display and a 4 line x 20 character display I had attached to the mega.

Rick

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Re: 32x16 LED Matrix Color

Post by us682112 »

Okay, I've discovered my problem - I think. Per the suggestion, I'm trying to use an Adafruit RGB Matrix Shield on Arduino Mega 2560 R3. The RGB matrix shield does indeed fit on the Mega, but I never could get test code to look anything close to meaningful.
Tracing the RGB Matrix on Mega connection, pins R1, G1, B1, R2, G2 & B2 map to digital pins 2 - 7.
In the Connecting with Jumper Wires post (https://learn.adafruit.com/32x16-32x32- ... mper-wires) it states for a Mega, R1, G1, B1, R2, G2 and B2 need to connect to pins 24 - 29.
I wondered if I could re-map these in header file, but after finding my way to the RGBmatrixPanel.cpp source code (https://github.com/adafruit/RGB-matrix- ... xPanel.cpp), it says starting on line 87:
87 #if defined(__AVR_ATmega1280__) || defined(__AVR_ATmega2560__)
88 // Arduino Mega is now tested and confirmed, with the following caveats:
89 // Because digital pins 2-7 don't map to a contiguous port register,
90 // the Mega requires connecting the matrix data lines to different pins.
91 // Digital pins 24-29 are used for the data interface, and 22 & 23 are
92 // unavailable for other outputs because the software needs to write to
93 // the full PORTA register for speed.

Bottom line, the Mega can't use digital pins 2 - 7. I might be able to use the shield to connect 10 of the 16 pins, or just get an Uno since the Skee Ball project is done. Please correct me if I'm wrong and appreciate the help. Thanks.

Rick

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Re: 32x16 LED Matrix Color

Post by adafruit_support_carter »

Oh, good find. Forgot (or overlooked) that there are caveats for that shield with a Mega. Sorry about that.

It's also mentioned here:
https://learn.adafruit.com/32x16-32x32- ... rix-shield
The shield does not directly work with the Arduino Mega — additional jumper wires are needed to pins off the shield — see the “Jumper Wires” page for pinouts, or consider making your own Mega proto shield for that board.
and here under COMPATIBLE HARDWARE:
https://learn.adafruit.com/32x16-32x32- ... re-3073477

So, yah, sorry for not catching that sooner, but using this with a Mega is probably going to be a pain. Those jumper wire connection setups always seem to have connection issues.

Sounds like you have an UNO available? Just using that is probably easiest.

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Re: 32x16 LED Matrix Color

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No problem - it's always a good thing when I learn something, and yeah should have a Uno at the door when I get home. I'm bound and determined to make the Matrix work...

Rick

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