Hi,
I bought four of these 64x64 panels from AliExpress. They were only £9 (before tax) at time of purchase:
P3 Full Color LED Sigital Sign HUB75 RGB Pixel Display LED Display Module Indoor LED Video Wall Large Screen 192*192mm
(Yes, Sigital)
a.aliexpress*com/_EwTTwtW
I’ll split this post up due to the error: new users can only include one media item per post…
They have the E line on pin 8 (according to the hidden HUB75 label) and chips labelled DP5125D.
I have connected a panel using an uncased Pi400 with an Adafruit RGB Bonnet and soldered jumper E>8 as instructed. I am powering with a 5V 12A PSU (I checked 5V by metering at panel input).
I have spent hours over the evenings experimenting with all the rpi-led commandline options listed in the readme such as multiplexing, and when I run Demo 0 it only displays corrupt static rectangles.
Weirdly, I have occasionally seen it display something loosely resembling the intended animated output (except red only and stripes missing) when I have cut power to the panels.
After looking around I see the chip was mentioned in github issues with no resolution, but also that Ironsheep has added support for the DP5125D in his HUB75 LED Matrix Driver after a discussion linked below with user, ke4pjw.
ke4pjw wrote:
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Success! Thank you @“Stephen Moraco” ! Here is the secret sauce for the DP5125D
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It is 1/8 scan. Colors are not swapped and display is not rotated.
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isp_hub75_hwGeometry.spin2
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PANEL_DRIVER_CHIP = hwEnum.CHIP_MANUAL_SPEC | hwEnum.LAT_POSN_OVERLAP | hwEnum.LAT_STYLE_OFFSET | hwEnum.SCAN_4
PANEL_ADDR_LINES = hwEnum.ADDR_ABC
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isp_hub75_hwBuffers.spin2
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DISP0_MAX_PANEL_COLUMNS = 64
DISP0_MAX_PANEL_ROWS = 32
DISP0_ROTATION = hwEnum.ROT_NONE
Ironsheep wrote:
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“I’ve just released v3.0.1 of RGB LED Matrix Driver. The changes are:
[…]
Add support for panels using DP5125D chips”
My aim is to have the four panels connected in a chain (I realise I may need a stronger PSU) and displaying Pico8 using:
Every component of this project is new to me so I expect I made a mistake with my matrix purchase. I wanted to make sure I had learned and tried as much as possible before posting here and asking for help.
If somebody could help, I’d like to know:
• Is there any way to get these working with rpi-led or for this will I need to buy new panels with either an FM626A or FM6127 chipset? Also I have only read mention of these two chips - are there others that are compatible?
• Can I use these panels (just to display anything and go ooooh) with other Pi software and without buying extra hardware such as the required Parallax adapter in my earlier link?
Hi
The driver DP5125 is a a completely standard driver, and is definitely supported by this software. If you have problems, then it is not the driver.
Write more about the panel - what is the number of scans? Also, a clear photo of the back of the panel could helps.
Look, what other chips are on it, besides 5125? There should be at least two more types of chips - a multiplexer for switching lines and a buffer. The type of multiplexer can also affect whether the matrix works or not.
Thank you for your help.
Here is a clearer photo of the panel rear.:
Here are the other chips:
The U chips I think are labelled as:
CHIPONE
ICN74HC245TS
D66210EA
The T chips are labelled:
RUC7258D
0AE15875
As for the number of scans there is not this kind of technical information in the AliExpress item description, nor included with the panels. I have found some other listings which use the same product picture and state the scan rate as 1/32. However I hesitated to even mention this and would not treat it as reliable. This kind of product info is so inconsistent and some item photos in the same description contradict eachother. Here it is though:
I don’t suppose this helps?..
I’m guessing probably not because at 240 fps we wouldn’t be able to see anything finer than the quarter rows displayed here anyway. But after the effort I may as well include it just in case.
The TOP row of each band is 35 LED rows from the next top row, as captured.
it’s a buffer chip
this one is multiplexer.
The good news that the multiplexer is of the most common, “138 type”.
It’s means that your panel should be a fully compatible with the library. So the problem is either in your sketch or in the connections.
Please show what command line you used to run the code. Did you change any connections relative to REadme?
My command line (from inside the examples folder) typically begins:
Sudo ./demo -D0 --led-rows=64 --led-cols=64 --led-chain=1 --led-slowdown-gpio=2 --led-gpio-mapping=adafruit-hat
In addition I’ve tried playing with the parameters in the GitHub readme. Mostly combinations of
–led-multiplexing= (0 to 18)
–led-row-addr-type= (0 to 4)
I’ve also tried different --led-slowdown-gpio settings.
For wiring I really don’t know how I could connect a single panel any differently. I have the adafruit bonnet plugged into the gpio, then an IDC cable (I’ve tried switching different cables) connecting the bonnet to the HUB75 connector on the panel. The power cable is currently connected from the panel to the screw terminals of the adafruit bonnet, and then I have a power lead connecting the bonnet to a 5v 12a PSU. I have also had the panel connected directly to the PSU and I have fine-adjusted the PSU’s pot to confirm a 5v reading when probing the panel’s power input.
I am using a pi400 which I removed from its containing case/keyboard (for better GPIO connection until an extension cable arrives).
Could there be a compatibility issue with the pi400? I read of someone using one successfully with this library to run pico8-led so I thought it would be fine.
This was a new Pi bought for this purpose. I used Pi imager and installed ‘Raspberry Pi OS Lite (64-bit)’ on a new SD Card. When I installed rpi-rgb-led-matrix I selected the convenience option. I have today tried a reinstall of the library.
What do you mean by sketch?
You can omit these two options or uses a “0” for both because your panel is compatible with default library settings.
As for connections, I recommend checking the reliability of all contacts, especially the ground connection between the pi400, the panel, and the power supply.
Unfortunately, I can’t advise anything else, since I don’t have much experience.
Thanks for all your help, board707. I’ve learned a lot from you.
I have a gpio extension cable on the way which can provide a better connection to the Adafruit bonnet* and I can try this on my son’s Pi Zero 2W.
The current connection is pretty shallow. I tested continuity on a few pins but maybe it’s a bit flakey.
Well I have now tried with a Pi Zero 2W (just swapped the SD card over) and the result is exactly the same.
By the way if I disconnect the 5v supply so that the panel is receiving no power through its dedicated input then it displays an interesting mess of red which looks vaguely like the intended rotating square.
When I reconnect the 5v it snaps back to corrupt brightly coloured stripes like I showed earlier.
Could this indicate a power issue? A short somewhere? Is the red mess of interference that I’ve shown the normal result when driven without 5v connected?
After trying:
Two Pis
Three software installations
Five panels from two suppliers
Three PSUs
Many different cables
I finally realised that my problem was the one common link. The Adafruit bonnet.
I used hzeller’s wiring guide to connect an IDC breakout cable directly to the GPIO pins, set gpio mapping to regular and then immediately saw a lovely stable and bright image. It looks amazing.
I have seen on the Adafruit forums that my problem is common. Several instances with the same symptoms of stuck random stripes of colour dating back to 2020. Looks like a bad batch of bonnets went out.
Anyway, all working now. Thank you board707 for your help.
The struggle I could have saved if I had figured this out in the first place! If I could edit this thread I would as the title is misleading.
oh boy, sorry to hear that. Yeah, it’s a bit sad that adafruit is still selling those non standard wired bonnets that are so much inferior to the electrodragon active-3 boards. Please consider buying those instead, they only cost a few dollars plus the time for shipping.
Thank you. For the record I bought the Adafruit bonnet from ThePiHut.
I will now order the electrodragon board. It seems a no-brainer. I originally bought a part I believed was suitable from ThePiHut as they’re a really nice store that I’ve used previously for my son’s projects and their shipping is fast here in the UK - but that time-save didn’t work out. What a shame. For over a week I thought I was doing something wrong because the most suspicious common link was myself.
To be honest the Electrodragon board is confusingly cheap. At first I wondered if the $3 price would only include a bare PCB, or a gerber file!
Also it will be good to be able to run my arrangement as two chains with the Elctrodragon. I would like to remove the slight join line caused by the opposing panel/RGB orientation, and after trying out the mapper options I am under the impression that dual chains are the only way to map both panel rows upright with this library. Without writing a custom mapper anyway.
