new P8 32*16 1/4 scan panel

[saka2080]

I have been trying to display a dot and a char on this P8 32x16 1/4 scan rgb matrix panel, but not succeeded. I am using blue pill and arduino IDE and STLink to burn the program. Sometimes, the matrix shows garbage pixels lit and sometimes it is totally blank. I have connected pins as:
R0- PA0 G0-PA1
B0- PA2 GND-GND
R1- PA3 G1-PA4
B1- PA5 GND-GND
A- PB6 B-PB5
C- PB4 GND-GND
CLK- PA15 LAT-PB7
OE- PB0 GND-GND

I used the following code:

#include "DMD_RGB.h"
//Number of panels in x and y axis
#define DISPLAYS_ACROSS 1
#define DISPLAYS_DOWN 1
#define ENABLE_DUAL_BUFFER false
// ==== DMD_RGB pins ====
// mux pins - A, B, C... all mux pins must be selected from same port!
#define DMD_PIN_A PB6
#define DMD_PIN_B PB5
#define DMD_PIN_C PB4
#define DMD_PIN_D PB3
#define DMD_PIN_E PB8
// put all mux pins at list
uint8_t mux_list[] = { DMD_PIN_A , DMD_PIN_B,DMD_PIN_C};

// pin OE must be one of PB0 PB1 PA6 PA7
#define DMD_PIN_nOE PB0
#define DMD_PIN_SCLK PB7

// Pins for R0, G0, B0, R1, G1, B1 channels and for clock.
uint8_t custom_rgbpins[] = { PA15, PA0,PA1,PA2,PA3,PA4,PA5 }; // CLK, R0, G0, B0, R1, G1, B1

DMD_RGB <RGB32x16plainS4, COLOR_4BITS> dmd(mux_list, DMD_PIN_nOE, DMD_PIN_SCLK, custom_rgbpins, DISPLAYS_ACROSS, DISPLAYS_DOWN, ENABLE_DUAL_BUFFER);

DMD_Standard_Font Arial_Black_F(Arial_Black_16);

void setup(void)
{
//enableDebugPorts();
// initialize DMD objects
dmd.init();

dmd.drawChar(0, 0, 'A', 3, 0) ;
dmd.drawPixel(10, 10, 5);
dmd.swapBuffers(true);
//
delay(5000);
}
`

[board707]

P8 32x16 1/4 scan rgb matrix panel

Hi!
First of all - are you sure that it is a 1/4 scan? The labels on the panel is not clear about this, and panel has A, B and C pins - it is typically for 1/8 scan and not for 1/4.

I can't read chip labels on your photo - do you know the driver and multiplexor type of the panel?

[saka2080]

One IC is readable ,it is TC4538. I guess it is 1/4 scan, because it shows P8_1_4_3535_PR4538_HSD_32x16_NRES in the label.

[saka2080]

Thank you for your prompt reply. Even I used
DMD_RGB <RGB32x16plainS8, COLOR_4BITS> dmd(mux_list, DMD_PIN_nOE, DMD_PIN_SCLK, custom_rgbpins, DISPLAYS_ACROSS, DISPLAYS_DOWN, ENABLE_DUAL_BUFFER);
but display did not show anything.

[board707]

How do you upload the code to your STM board? Via St-Link or via USB bootloader?

[saka2080]

Via St-link

[board707]

When you using a St-link, pins PB3, PB4 and PA15 are blocked.
To release these pins add a line

enableDebugPorts();

just at the start of setup() function and test again.

[saka2080]

No luck. I used enableDebugPorts(); but display did not show anything.

But when I do using RGBmatrixPanel using mega2560 using the code below the display works with 2 panel. But I don't know why it is not working with bluepill

#include "gamma.h"
#include <Adafruit_GFX.h>    // Core graphics library
#include "digital_7_mono16pt7b.h"
#include "RGBmatrixPanel.h" // Hardware-specific library (Ruud’s version)
#define clear() fillScreen(0)

#define CLK 11 // MUST be on PORTB! (Use pin 11 on Mega)
#define LAT 10
#define OE 9
#define A A0
#define B A1
#define C A2

RGBmatrixPanel matrix(A, B, C, CLK, LAT, OE, false,2); // 1 = amount of panels

void setup() {
matrix.begin();
  matrix.setTextSize(1);
  matrix.setCursor(2,25);
  matrix.setTextColor(matrix.Color333(7,0,0));
  matrix.print("91");
  matrix.setCursor(34,9);
  matrix.print("91");
}

[board707]

Could you replace the setup() and loop() functions to this code:

void setup(void)
{
   enableDebugPorts();
    dmd.init();
    fg = dmd.Color888(0, 0, 255);
    dmd.setBrightness(50);
}

void loop(void) {
    // fill the matrix with points row by row
    for (int i = 0; i < dmd.height(); i++) {
        for (int j = 0; j < dmd.width(); j++) {
            dmd.drawPixel(j,i, fg);
            delay(30);
        }
    }
    // clear the screen
    dmd.fillScreen(bg);
}

[saka2080]

I used the following code with the following setup.

But the display did not show a single pixel. I verified the pin to pin connections too.

/*--------------------------------------------------------------------------------------
 Demo for RGB panels

 DMD_STM32a example code for STM32F103xxx board

 Pattern test for 32x16 1/2 1/4 RGB panels
 ------------------------------------------------------------------------------------- */
 #include "DMD_RGB.h"

//Number of panels in x and y axis
#define DISPLAYS_ACROSS 1
#define DISPLAYS_DOWN 1

// Output buffering - false
#define ENABLE_DUAL_BUFFER false

// ==== DMD_RGB pins ====
// mux pins - A, B, C... all mux pins must be selected from same port!
#define DMD_PIN_A PB6
#define DMD_PIN_B PB5
#define DMD_PIN_C PB4
//#define DMD_PIN_D PB3
//#define DMD_PIN_E PB8
// put all mux pins at list
//uint8_t mux_list[] = { DMD_PIN_A , DMD_PIN_B , DMD_PIN_C , DMD_PIN_D , DMD_PIN_E };

uint8_t mux_list[] = { DMD_PIN_A , DMD_PIN_B , DMD_PIN_C };

// pin OE must be one of PB0 PB1 PA6 PA7
#define DMD_PIN_nOE PB0
#define DMD_PIN_SCLK PB7

// Pins for R0, G0, B0, R1, G1, B1 channels and for clock.
// By default the library uses RGB color order.
// If you need to change this - reorder the R0, G0, B0, R1, G1, B1 pins.
// All this pins also must be selected from same port!
uint8_t custom_rgbpins[] = { PA15, PA0,PA1,PA2,PA3,PA4,PA5 }; // CLK, R0, G0, B0, R1, G1, B1

// Fire up the DMD object as dmd<MATRIX_TYPE, COLOR_DEPTH>

// For pattern testing use one of matrix below:
// RGB32x16plainS4         - 32x16 1/4 Binary mux
// RGB32x16plainS4_DIRECT  - 32x16 1/4 DIRECT mux
// RGB32x16plainS2         - 32x16 1/2 Binary mux

DMD_RGB <RGB32x16plainS8, COLOR_4BITS> dmd(mux_list, DMD_PIN_nOE, DMD_PIN_SCLK, custom_rgbpins, DISPLAYS_ACROSS, DISPLAYS_DOWN, ENABLE_DUAL_BUFFER);

uint16_t bg = 0;  // background - black
uint16_t fg = 0;  // foreground

void setup(void)
{
    dmd.init();
    fg = dmd.Color888(0, 0, 255);
    dmd.setBrightness(50);
}

void loop(void) {
    // fill the matrix with points row by row
    for (int i = 0; i < dmd.height(); i++) {
        for (int j = 0; j < dmd.width(); j++) {
            dmd.drawPixel(j,i, fg);
            delay(30);
        }
    }
    // clear the screen
    dmd.fillScreen(bg);
}

[board707]

Sorry, I forgot to add the line enableDebugPorts(); to the setup()

void setup(void)
{
   enableDebugPorts();
    dmd.init();
    fg = dmd.Color888(0, 0, 255);
    dmd.setBrightness(50);
}

without this line any tests is a waste of the time.

[saka2080]

I have been trying but no result. But I found that if there is some garbage data (by turing ON/OFF power supply of panel), the dmd.setBrightness() is working.

[board707]

We don't know what driver your board has, it may not be compatible with the library. But, since the panels work with the RGBmatrixPanel library, they should also work with this code.
Unfortunately, I have no more ideas for now...

[saka2080]

it is TC4538. the label is P8_1_4_3535_PR4538_HSD_32x16_NRES. What do you suggest so that I can test it without using the library?

[board707]

No, the 4538 chip is not a driver, it is multiplexor. Every panel contains at least two types a chips - a driver and a multiplexor.
We do not know the driver, but it seems to be compatible because the panel works with RGBMatrixPanel library.
So I don't know the reason why it not work s. I will try to figure out the issue.

[board707]

Hi
As I see in the pictures, your panel seems to be 1/8 scan.
Could you try the code from comment with color mode changed to COLOR_4BITS_Packed:

DMD_RGB <RGB32x16plainS8, COLOR_4BITS_Packed> dmd(mux_list, DMD_PIN_nOE, DMD_PIN_SCLK, custom_rgbpins, DISPLAYS_ACROSS, DISPLAYS_DOWN, ENABLE_DUAL_BUFFER);