Dear Sir, i am also tring but not getting success, May you help me out.

[Rajkumar821108]

I solved the problem of matrix panel with p8 20x40 pixels 1/5 scan rate. I managed to get it working with library https://github.com/2dom/PxMatrix#shiftreg_abc_bin_de. now i have problem with p10 rgb matrix panel which has 1/4 scan rate. there are only rows A and B. Again the same library ran, but one line works in reverse.

@oldcity83

I have same problem with P8 20*40 1/5, can you help me to solve this problem.

Originally posted by @saka2080 in #204

[board707]

Hi @Rajkumar821108 !
You re-posted the message written by @oldcity83 in 2023 and cited by @saka2080 in 2024.
What's you mean with it?

Could you please express your own problems rather than copy-paste other's issues?

[Rajkumar821108]

Hi @board707 !
you check it,

[Rajkumar821108]

Dear Sir, I am trying for a long time but haven't got any success yet, please help me,

[board707]

I am sorry, but the words "trying for a long time" express nothing without showing what exactly you trying.
Please read the #828 as an example, how to explain the issue and what you you have to do to solve the issue.

[juber23567]

Please Explain in Details

[Rajkumar821108]

Dear Sir, i am using p8 panel having 1/5 scan rate in 20X40 pixel, P8-(2727-3535)5S-40X20-S3 AND XR25/A12/31/LK/P8-RGB(3535)Z12(5125D)/0328/10000-00457 printed on back side. i have tried with libraries like PxMatrix-master,ESP32-HUB75-MatrixPanel-I2S-DMA-master,Adafruit-GFX-Library-master but still facing problem, whereas these libraries run proper with 1/4th scan P10Display in 16x32 pixel. any idea how i glow a pixel on P8 or other supported libraries?

[board707]

Please show a clear photo of the panel back side.
Could you try to read a marking on all types of chips on the panel?

[Rajkumar821108]

Dear Sir, the panel designed with ICs DP5125D-30piece,RUC7258D-4piece,74HC245KAJ-3piece.

[board707]

Thank you.

Please open the Pixel_Mapping_Test.ino library example, save it under a new name and replace
CustomPxBasePanel ::getCoords() method to the code below:

inline VirtualCoords CustomPxBasePanel ::getCoords(int16_t x, int16_t y) {

  coords = VirtualMatrixPanel::getCoords(x, y); // first call base class method to update coords for chaining approach

  if ( coords.x == -1 || coords.y == -1 ) { // Co-ordinates go from 0 to X-1 remember! width() and height() are out of range!
    return coords;
  }


if (((coords.y / 5)%2) == 0)
        {
            coords.x += ((coords.x / panelResX) + 1) * panelResX; // 1st, 3rd 'block' of 8 rows of pixels, offset by panel width in DMA buffer
        }
        else
        {
            coords.x += (coords.x / panelResX) * panelResX; // 2nd, 4th 'block' of 8 rows of pixels, offset by panel width in DMA buffer
        }

       coords.y = (coords.y / 10) * 5 + (coords.y % 5);
  return coords;
} 

Also fix the panel dimensions to 40x20 in the code.

Than run it on the real panel and show the resulting video.

(please do not reduce inter-pixel delay (30ms) in the main loop. )

[Rajkumar821108]

Dear Sir, i am using the code :/*************************************************************************
Description:

The underlying implementation of the ESP32-HUB75-MatrixPanel-I2S-DMA only
supports output to HALF scan panels - which means outputting
two lines at the same time, 16 or 32 rows apart if a 32px or 64px high panel
respectively.
This cannot be changed at the DMA layer as it would require a messy and complex
rebuild of the library's internals.

However, it is possible to connect QUARTER (i.e. FOUR lines updated in parallel)
scan panels to this same library and
'trick' the output to work correctly on these panels by way of adjusting the
pixel co-ordinates that are 'sent' to the ESP32-HUB75-MatrixPanel-I2S-DMA
library.

**************************************************************************/

/* Use the Virtual Display class to re-map co-ordinates such that they draw
correctly on a 32x16 1/4 or 64x32 1/8 Scan panel (or chain of such panels).
*/
#include "ESP32-VirtualMatrixPanel-I2S-DMA.h"

// Define custom class derived from VirtualMatrixPanel
class CustomPxBasePanel : public VirtualMatrixPanel
{
public:
using VirtualMatrixPanel::VirtualMatrixPanel; // inherit VirtualMatrixPanel's constructor(s)

protected:

VirtualCoords getCoords(int16_t x, int16_t y);  // custom getCoords() method for specific pixel mapping

};

// custom getCoords() method for specific pixel mapping
inline VirtualCoords CustomPxBasePanel ::getCoords(int16_t x, int16_t y) {

coords = VirtualMatrixPanel::getCoords(x, y); // first call base class method to update coords for chaining approach

if ( coords.x == -1 || coords.y == -1 ) { // Co-ordinates go from 0 to X-1 remember! width() and height() are out of range!
return coords;
}

if (((coords.y / 5)%2) == 0)
{
coords.x += ((coords.x / panelResX) + 1) * panelResX; // 1st, 3rd 'block' of 8 rows of pixels, offset by panel width in DMA buffer
}
else
{
coords.x += (coords.x / panelResX) * panelResX; // 2nd, 4th 'block' of 8 rows of pixels, offset by panel width in DMA buffer
}

   coords.y = (coords.y / 10) * 5 + (coords.y % 5);

return coords;
}

// Panel configuration
#define PANEL_RES_X 40 // Number of pixels wide of each INDIVIDUAL panel module.
#define PANEL_RES_Y 20 // Number of pixels tall of each INDIVIDUAL panel module.

// Use a single panel for tests
#define NUM_ROWS 1 // Number of rows of chained INDIVIDUAL PANELS
#define NUM_COLS 1 // Number of INDIVIDUAL PANELS per ROW

// Chain settings, do not cnahge
#define SERPENT true
#define TOPDOWN false
#define VIRTUAL_MATRIX_CHAIN_TYPE CHAIN_BOTTOM_RIGHT_UP

// placeholder for the matrix object
MatrixPanel_I2S_DMA *dma_display = nullptr;

// placeholder for the virtual display object
CustomPxBasePanel *FourScanPanel = nullptr;

/******************************************************************************
Setup!
******************************************************************************/
void setup()
{
HUB75_I2S_CFG mxconfig(
PANEL_RES_X * 2, // DO NOT CHANGE THIS
PANEL_RES_Y / 2, // DO NOT CHANGE THIS
NUM_ROWS * NUM_COLS // DO NOT CHANGE THIS
//,_pins // Uncomment to enable custom pins
);

mxconfig.clkphase = false; // Change this if you see pixels showing up shifted wrongly by one column the left or right.

// OK, now we can create our matrix object
dma_display = new MatrixPanel_I2S_DMA(mxconfig);

// let's adjust default brightness to about 75%
dma_display->setBrightness8(40); // range is 0-255, 0 - 0%, 255 - 100%

// Allocate memory and start DMA display
if ( not dma_display->begin() )
Serial.println("****** !KABOOM! I2S memory allocation failed ***********");

dma_display->clearScreen();
delay(500);

// create FourScanPanellay object based on our newly created dma_display object
FourScanPanel = new CustomPxBasePanel ((*dma_display), NUM_ROWS, NUM_COLS, PANEL_RES_X, PANEL_RES_Y, VIRTUAL_MATRIX_CHAIN_TYPE);

}

void loop() {
for (int i = 0; i < FourScanPanel->height(); i++)
{
for (int j = 0; j < FourScanPanel->width(); j++)
{
FourScanPanel->drawPixel(j, i, FourScanPanel->color565(255, 0, 0));
delay(30);
}
}
delay(2000);
dma_display->clearScreen();
} // end loop

P8_RGB.mp4

[Rajkumar821108]

Sir, May you change for a charactor display

[board707]

Thanks for your video.
I'm at work now and will answer you later.

[board707]

Please change the code of the getCoords() method this way and show the video:

inline VirtualCoords CustomPxBasePanel ::getCoords(int16_t x, int16_t y)
{
  coords = VirtualMatrixPanel::getCoords(x, y); // first call base class method to update coords for chaining approach

  if ( coords.x == -1 || coords.y == -1 ) { // Co-ordinates go from 0 to X-1 remember! width() and height() are out of range!
    return coords;
  }

uint8_t pxbase =4;   // pixel base
if  ((((coords.y / 5)%2) == 0) ^ ((coords.x/pxbase) % 2))
    {
   coords.x += (coords.x / pxbase) * pxbase; // 2nd, 4th 'block' of 8 rows of pixels, offset by panel width in DMA buffer
   }
else
  {
   coords.x += ((coords.x / pxbase) + 1) * pxbase; // 1st, 3rd 'block' of 8 rows of pixels, offset by panel width in DMA buffer
   }

       coords.y = (coords.y / 10) * 5 + (coords.y % 5);
  return coords;
}

[Rajkumar821108]

Thankyou Sir, I will check tomorrow and update you.

…

On Tue, 16 Sept, 2025, 7:46 pm board707, ***@***.***> wrote: *board707* left a comment (mrcodetastic/ESP32-HUB75-MatrixPanel-DMA#836) <#836 (comment)> Please change the code of the getCoords() method this way and show the video: inline VirtualCoords CustomPxBasePanel ::getCoords(int16_t x, int16_t y) { coords = VirtualMatrixPanel::getCoords(x, y); // first call base class method to update coords for chaining approach if ( coords.x == -1 || coords.y == -1 ) { // Co-ordinates go from 0 to X-1 remember! width() and height() are out of range! return coords; } uint8_t pxbase =4; // pixel base if ((((coords.y / 5)%2) == 0) ^ ((coords.x/pxbase) % 2)) { coords.x += (coords.x / pxbase) * pxbase; // 2nd, 4th 'block' of 8 rows of pixels, offset by panel width in DMA buffer } else { coords.x += ((coords.x / pxbase) + 1) * pxbase; // 1st, 3rd 'block' of 8 rows of pixels, offset by panel width in DMA buffer } coords.y = (coords.y / 10) * 5 + (coords.y % 5); return coords; } — Reply to this email directly, view it on GitHub <#836 (comment)>, or unsubscribe <https://github.com/notifications/unsubscribe-auth/BOLUEYBWKV5CGLWUWIYGN4L3TALUJAVCNFSM6AAAAACGRHFUZ6VHI2DSMVQWIX3LMV43OSLTON2WKQ3PNVWWK3TUHMZTEOJYHE3TQNZTGQ> . You are receiving this because you were mentioned.Message ID: ***@***.*** com>