I bought my first 32x32 LED matrix, but it has no 'D' connection...?

Hi there,

Just to set the scene, I'm new to the world of Arduino and these big LED panels, but I do have a bit of experience playing with the TI MSP430 LaunchPad boards and other random bits of electronics, so I'm not a complete newbie.

Anyway, I recently imported one of these 32x32 LED panels from China, the kind you see for sale on Adafruit, but after excitedly wiring it up to have a play with it I've been left confused as to why the apparently required 'D' connection isn't labelled on the PCB - and the pin it should be on is tied to ground...

Do I not need the 'D' pin to address all the LEDs properly? If so I haven't been able to find any documentation regarding how I should wire it up. All of Adafruit's tutorials and example code reference all the A,B,C and D pins for driving a 32x32 panel, it's only missing when driving 32x16.

Here's a picture of the back of the board:

Here's how it looks on the final screen of the Adafruit testshapes_32x32 example:

It seems as though the first 8 rows of the screen (which should say "Ada") are being drawn on top of the second 8 rows (which should say "fruit"). Whatever input is put on the 1st row appears to be duplicated on the 9th row too, with a bit of ghosting also on the 10th - as evidenced by when I pause the sketch on the "draw a pixel at 0,0" line; it actually draws this:

Here's how it looks when wired up as if it was a 32x16 panel running the Adafruit scrolltext_16x32 example:

As you can see, the text is coming out fine (in the middle at least), there's just a similar re-drawing issue as above where the text is drawn on top of itself - again, from the 9th row.

Any suggestions? There's the obvious possibility I'm just doing something completely stupid, or did I buy a useless panel?

It looks like your panel is ok. But it does not work in quite the same way as the AdaFruit ones.

Post a link to where you bought it.

I bought the LED panel from AliExpress, this one specifically: https://www.aliexpress.com/item/Indoor-P7-62-LED-Module-244mm-x-244mm-32x32matrix-1-16-Scan-SMD3528-LED-for-7/32730524423.html

Although the images for the panels on that page show a 'D' pin on the header...

I was aware that all these panels can have a slightly different pin layout, but I didn't expect to receive one without all the regular connections!

It's a pretty useless picture, very fuzzy.


Did you ever get this working?? I am also having this same problem. The display appears to be divided into 8 sections 4 down and 2 across. The pixels in column 1 are repeated in column 2. Also the second row is displaying the pixels from the first row. Any ideas?

I also have a similar problem, 32x32 with only 3 row address pins.

I believe what is happening is that the newer 32x32 matrix panels like we have are actually set up like 2 panels that are 16 wide by 32 tall and the data should be first shifted in for the left side of the display as if it was 16x32 and then the data for the right half should be shifted in as if it was a second 16x32 display.

I spent a lot of time reading through the library and tinkering with it, but it is a bit foreign to me and I have not been able to figure out how to modify it to work this way.