Interfacing with 80*40 Panels

[hemanthkd]

I got the new release of Qiangli P4 80*40 panels, when tried interfacing, I faced a problem that rows from 16 to 20 as well as 36 to 40 are not turning on. Hope you would help us

[hemanthkd]

Image, which I have given as input is download.jpg And the result I got is Result.jpeg

[hzeller]

You are not providing enough info. How did you connect it and what are the commandline options you provide to the program?

[hemanthkd]

We took total of 8 panels in two chains and arranged in U mapper in two chains with the Active-3. So in one chain we place 4 panels in U-shape so that first two will be normal and other 2 will be upside down. And the commands we followed are: pi@raspberrypi:~/rpi-matrix-pixelpusher/matrix/utils $ sudo ./led-image-viewer --led-rows=40 --led-cols=80 --led-pixel-mapper="U-mapper" --led-chain=4 --led-parallel=2 --led-no-hardware-pulse download.jpg

[hzeller]

with 40 height, you need the E address line configured on the active3 adapter. did you?

[hemanthkd]

I am extremely sorry that just now I have found the E pin on the 8th pin and have configured accordingly by connecting E pin and 8th, 4rth pin and GND on the active adapter but the result is the exact inverse of the previous output and is as follows: as follows

[hemanthkd]

When I am not connecting the E pin, I am getting the inital output(Result.jpeg).

And when I have connected the Epin to the 8th pin on the adapter I found this output(UpdatedResult.jp g). It is something like if we merge both the outputs then its a complete output. Please help me out in resolving this issue

[hzeller]

It looks wierd as if the E pin is permanently high. Can you double-check that you have your UART disabled, as the E-line is sharing a pin with that, and maybe that interferes. Also double-check the soldering on the relevant pins of the active3 board.

[hemanthkd]

I have tried disabling UART using "sudo systemctl disable hciuart" but still the same result is taking place, but when I tried E pin connecting to GND physically, then the other part of the screen is turning on as mentioned in the above pictures

[hemanthkd]

And I also checked the solderings on the adapter board, those are clear and perfect. i hope the main issue is only due the permanent state of GPIO 15. Please help me out

[hzeller]

did you disable the uart by putting enable_uart=0 in /boot/config.txt ? Otherwise the system might attempt to write console messages to it.

[hemanthkd]

Yes it is already present.

[hzeller]

so your gpio15 is stuck, you have to get it unstuck. There is something going on with your hardware, either the breakout board or the Pi. Can't help remotely here, you have to systematically figure out where the problem is: measure the output while toggling it, replace hardware...

[hemanthkd]

Should i use a new pi

[hzeller]

depending if you find that the GPIO pin has a hardware fault

[hemanthkd]

I have tried with another pi and found the same issue. But the thing is GPIO15 is always showing 3.3V, does the usage of xrdp effects the GPIO 15.

[hemanthkd]

can I use some other pins instead of GPIO 15 as I was not using the 3rd chain in the adapter

[hzeller]

If you are using xrdp, this tells me that you are using a more complicated system than needed. Please make sure to use the minimal configuration as mentioned in the documentation. The other systems are known to have all kinds of additional packages installed that might mess with the output of the GPIO pins. You want to use the minimal raspbian and connect to it with ssh.

You can use other pins, the mapping is defined in the hardware-mapping.c file. You then of course have to re-route the wiring manually on the adapter board, e.g. by scratching off traces and wire them with some cable.

[hemanthkd]

As discussed I have changed the GPIO 15 to GPIO 21 and also manually routes the adapter board, but this time the default state of GPIO21 is not getting changed and I am sure that both 15 and 21 are working fine for a simple blinking led code

[davemaster]

Can You please provide a picture of your panels and your RPi connection (good quality pictures) so we can figure it the solution to help You?

[hemanthkd]

I hope there is an issue with the command to enable the E line, while all the rest of the things are working fine. Here are some pictures of my panels and RPI connection.Link:https://drive.google.com/drive/folders/1dqstTAMj7qeeqWiZ4l9rJiKoGUE81TAL?usp=sharing

[davemaster]

I hope there is an issue with the command to enable the E line, while all the rest of the things are working fine. Here are some pictures of my panels and RPI connection.Link:https://drive.google.com/drive/folders/1dqstTAMj7qeeqWiZ4l9rJiKoGUE81TAL?usp=sharing

According Your pictures, You may have a connection problem. Try this, always, the simple first then the complex; so, try rpi-rgb-led-matrix with only ONE panel; also, use those cables link these https://www.sparkfun.com/products/11026; without the HAT. Try this, FIRST. Pictures or videos of this try please.

[hemanthkd]

The same issue has taken place even I have directly interfaced the single panel with pi directly Link for the pictures:https://drive.google.com/drive/folders/1u0MlPX2Oi_dZstOJsroZ5XfqVWDu4K12?usp=sharing

[hemanthkd]

When I have connected the single panel and when given the following command Command with cols=80, rows=64, all the LEDs are working fine, but the displayed image is missing with few parts as the Panel is having col=80 and rows=40. Below is the output image, when the first download.jpg is given as input

[hzeller]

Ah, that is interesting. So it is due to the odd size of the panel. I might have an idea where the problem is. Will check when I come home.

[hzeller]

Alright, can you try again with a fresh checkout ? Hopefully that should make the 40 row panel working with --led-rows=40.

[hemanthkd]

Thank you so much for your full support. Finally, I got the perfect output

[muharramapri]

Thank you so much for your full support. Finally, I got the perfect output

now i have problem like you before, can you help me? I use the 3rd chain in the adapter and the adapter that I use from Electrodragon and I have also disabled uart. please..