P10 32x16 LED panel 1/4 scan now works with Adafruit_GFX

Using Arduino LEDs and Multiplexing
24

Hi all! This is my first post on this forum. I created an account because of this very problem, because I have it, too :slight_smile: But it seems that this issue is slightly different with everyone.

I implemented Ruud's original code, but it did not solve my problem. My outdoor 32x16 1/4-scan panel seem to work OK by writing on lines 1 and 2 in correct order. Also the led colours work fine. But the panel output is messed up with two ways:
1: a single pixel does not appear as a single pixel, but more like some funny "vertical group of fours" depending on the coordinate I wish to place it.
2: Pixel mapping seems to be weird, too (see the pic). I tried to write: "-----" on the second line in wht/red/grn/blu/wht, but all I got was 4-pixel tall bars in weird order.

My panels have a silkscreen saying: "P10(3535)16X32-4S-M2.1"

I tried gusantor's code and I'm having similarities with the pixel "hopping" with an addition of the multiple vertical pixels (4 minus some) appearing on my panel.

It seems to me, that there is no universal standard as to how to build led displays. But I'm sure there must be a way to control each of them. There just must be - they wouldn't build them in millions in the first place if this was not the case... right? :slight_smile:

So here's my code:

#include <Adafruit_GFX.h>   // Core graphics library
#include <RGBmatrixPanel_1per4.h> // Hardware-specific library (Ruud's version) 

#define CLK 8  // MUST be on PORTB! (Use pin 11 on Mega)
#define LAT 10
#define OE  9
#define A   A0
#define B   A1
#define C   A2
#define D   A3
RGBmatrixPanel matrix(A, B, C, CLK, LAT, OE, false, 1); // 1 = amount of panels
void setup() {
  
  
  matrix.begin();

  matrix.setCursor(1, 9);   // next line
  matrix.setTextColor(matrix.Color333(7,7,7)); 
  matrix.print('-');
  matrix.setTextColor(matrix.Color333(7,0,0)); 
  matrix.print('-');
  matrix.setTextColor(matrix.Color333(0,7,0));
  matrix.print('-');
  matrix.setTextColor(matrix.Color333(0,0,7)); 
  matrix.print("-");
  matrix.setTextColor(matrix.Color333(7,7,7)); 
  matrix.print("-");

}

void loop() {
  // do nothing
}

And here's the pic:
http://s257.photobucket.com/user/knarf_69/media/-----_in_WRGBW.jpg.html?sort=3&o=0

Many thanks in advance for your patience and help! :slight_smile: