max7219 chained display showing mirrored text

Question

I'm using a max7219 like this one max7219. When I first tested my circuit, I used an 8x8 display and the code worked just fine. Now, after I modified the code with the one that can be found online at arduino code and changed the display with the chained one, the text appears to be mirrored on the matrix display.

.

Below, I'll attach part of the code. Please help me find the problem.

#include <MD_Parola.h>
#include <MD_MAX72xx.h>
#include <SPI.h>

// Define the number of devices we have in the chain and the hardware interface

#define MAX_DEVICES 4
#define CLK_PIN     13
#define DATA_PIN    11
#define CS_PIN      10

// Hardware SPI connection
MD_Parola P = MD_Parola(CS_PIN, MAX_DEVICES);
// Arbitrary output pins
// MD_Parola P = MD_Parola(DATA_PIN, CLK_PIN, CS_PIN, MAX_DEVICES);

void setup(void)
{
  P.begin();
  P.displayText("Hello", PA_CENTER, 0, 0, PA_PRINT, PA_NO_EFFECT);
}

void loop(void)
{
  P.displayAnimate();
}

Answer 1

Since version 3.0 MD_MAX72xx.h no longer supports that definition. Now the hardware type is defined as a parameter on creation (in the "Example" file you are using - not in MD_MAX72xx.h)

#define HARDWARE_TYPE MD_MAX72XX::FC16_HW
...
MD_Parola P = MD_Parola(HARDWARE_TYPE, CS_PIN, MAX_DEVICES);

Note that I've changed the hardware type from PAROLA_HW to FC_16.

Answer 2

Check the configuration in MD_MAX72xx.h file and ensure you have the right module selected.

For example there is a define

#define USE_PAROLA_HW   0

if your hardware is this item then turn off the other hardware settings and turn this one on so it reads as follows:

#define USE_PAROLA_HW   1

there many other settings if it is not there then you will have to experiment until you find the correct one.

Answer 3

In library, change #define USE_GENERIC_HW 0 to #define USE_GENERIC_HW 1 is the solution.

Answer 4

In latest version of #include <MD_Parola.h>, #include <MD_MAX72xx.h> you have to define the following and characters will display correctly.

#define HARDWARE_TYPE MD_MAX72XX::FC16_HW