I bought a board from Amazon that has eight 1088AS (8X8 LED) Modules. Each module is driven by a MAX7219 display driver. The LED sockets are perpendicular to the board rather than in line with the board. The input connection to the board is on the left, based on the IN – OUT marking on the modules.
I got the example working first with a NANO V3.
I am using the MD_Parola and MD_MAX72xx libraries. I started with the example sketch, “Parola_Scrolling”, and made minor customizations to work with the “8 in 1 Display Module”.
My customizations were:
· I used HARDWARE_TYPE: #define HARDWARE_TYPE MD_MAX72XX::FC16_HW
· I changed: #define MAX_DEVICES 8 instead of the example's 11
· I changed: uint8_t scrollSpeed = 75; instead of the default of 25 (faster)
· To reverse the scrolling direction: P.displayScroll("text", PA_LEFT, PA_SCROLL_RIGHT, 100);
· To reverse the scrolling direction: I used: scrollEffect = PA_SCROLL_RIGHT;
· P.displayText(curMessage, scrollAlign, scrollSpeed, scrollPause, scrollEffect, scrollEffect);
· To flip the text top/bottom and left/right, I used:
o P.setZoneEffect(0, true, PA_FLIP_UD);
o P.setZoneEffect(0, true, PA_FLIP_LR);
My connections were:
#define CLK_PIN 13
#define DATA_PIN 11 // Nano: 11
#define CS_PIN 10 // Nano: 10
Now, what I want to do is be able to change the message with a web page using an “UNO WiFi Rev 2” as a web server. So I tried to get the same Parola scrolling script working on the UNO before complicating things by adding the Web Page interface. But just substituting the UNO board and using the same connections didn’t work. The display randomly gets most or all modules showing all LEDs on occasionally one is OFF. (I am using a 5v external power supply connected to the Arduino Vin connection.) The serial messages work on the UNO but the LED modules don't.
I used the same connections on the NANO and UNO as listed above.
Any ideas on what is different about the UNO WiFi Rev2?
This is my sketch. Note I kept the example's opening notes
// Use the Parola library to scroll text on the display
//
// Demonstrates the use of the scrolling function to display text received
// from the serial interface
//
// User can enter text on the serial monitor and this will display as a
// scrolling message on the display.
// Speed for the display is controlled by a pot on SPEED_IN analog in.
// Scrolling direction is controlled by a switch on DIRECTION_SET digital in.
// Invert ON/OFF is set by a switch on INVERT_SET digital in.
//
// UISwitch library can be found at
// MD_MAX72XX library can be found at
//
/*
I modified the library example to drive the 8-module, single board array I bought from Amazon:
EC Buying MAX7219 Dot Matrix 8 in 1 Display Module for Arduino Microcontroller - Electronic SCM Control Drive LED
The LED sockets are perpendicular to the board rather than in line with the board.
I used a different HARDWARE_TYPE: #define HARDWARE_TYPE MD_MAX72XX::FC16_HW
I changed #define MAX_DEVICES 8 instead of the example's 11
I changed uint8_t scrollSpeed = 75; instead of the default of 25 (faster)
To reverse the scrolling direction:P.displayScroll("text", PA_LEFT, PA_SCROLL_RIGHT, 100);
I used: scrollEffect = PA_SCROLL_RIGHT;
To reverse the scrolling direction: I used: scrollEffect = PA_SCROLL_RIGHT;
scrollEffect = PA_SCROLL_RIGHT;
P.displayText(curMessage, scrollAlign, scrollSpeed, scrollPause, scrollEffect, scrollEffect);
To flip the text top/bottom and left/right, I used:
P.setZoneEffect(0, true, PA_FLIP_UD);
P.setZoneEffect(0, true, PA_FLIP_LR);
I changed the text of the messages, and added a one-time message with the sketch name
*/
#include <MD_Parola.h>
#include <MD_MAX72xx.h>
#include <SPI.h>
// set to 1 if we are implementing the user interface pot, switch, etc
#define USE_UI_CONTROL 0
#if USE_UI_CONTROL
#include <MD_UISwitch.h>
#endif
// Turn on debug statements to the serial output
#define DEBUG 0
#if DEBUG
#define PRINT(s, x) { Serial.print(F(s)); Serial.print(x); }
#define PRINTS(x) Serial.print(F(x))
#define PRINTX(x) Serial.println(x, HEX)
#else
#define PRINT(s, x)
#define PRINTS(x)
#define PRINTX(x)
#endif
// Define the number of devices we have in the chain and the hardware interface
/*
There are four HARDWARE)TYPEs defined in MD_MAX72xx.h
GENERIC_HW, ///< Use 'generic' style hardware modules commonly available.
FC16_HW, ///< Use FC-16 style hardware module.
PAROLA_HW, ///< Use the Parola style hardware modules.
ICSTATION_HW, ///< Use ICStation style hardware module.
*/
// NOTE: These pin numbers will probably not work with your hardware and may
// need to be adapted
//#define HARDWARE_TYPE MD_MAX72XX::PAROLA_HW
//#define HARDWARE_TYPE MD_MAX72XX::GENERIC_HW
//#define HARDWARE_TYPE MD_MAX72XX::ICSTATION_HW
#define HARDWARE_TYPE MD_MAX72XX::FC16_HW
#define MAX_DEVICES 8
#define CLK_PIN 13
#define DATA_PIN 11 // Nano: 11
#define CS_PIN 10 // Nano: 10
// HARDWARE SPI
MD_Parola P = MD_Parola(HARDWARE_TYPE, CS_PIN, MAX_DEVICES);
// SOFTWARE SPI
//MD_Parola P = MD_Parola(HARDWARE_TYPE, DATA_PIN, CLK_PIN, CS_PIN, MAX_DEVICES);
// Scrolling parameters
#if USE_UI_CONTROL
const uint8_t SPEED_IN = A5;
const uint8_t DIRECTION_SET = 8; // change the effect
const uint8_t INVERT_SET = 9; // change the invert
const uint8_t SPEED_DEADBAND = 5;
#endif // USE_UI_CONTROL
uint8_t scrollSpeed = 25; // default frame delay value is 25. bigger number is slower.
textEffect_t scrollEffect = PA_SCROLL_LEFT;
textPosition_t scrollAlign = PA_LEFT;
uint16_t scrollPause = 2000; // in milliseconds
// Global message buffers shared by Serial and Scrolling functions
#define BUF_SIZE 75
char curMessage[BUF_SIZE] = { "Parola_Scrolling_Example_Modified.ino" };
char newMessage[BUF_SIZE] = { "Hello! Enter new message in the Serial Monitor." };
bool newMessageAvailable = true;
#if USE_UI_CONTROL
MD_UISwitch_Digital uiDirection(DIRECTION_SET);
MD_UISwitch_Digital uiInvert(INVERT_SET);
void doUI(void)
{
// set the speed if it has changed
{
int16_t speed = map(analogRead(SPEED_IN), 0, 1023, 10, 150);
if ((speed >= ((int16_t)P.getSpeed() + SPEED_DEADBAND)) ||
(speed <= ((int16_t)P.getSpeed() - SPEED_DEADBAND)))
{
P.setSpeed(speed);
scrollSpeed = speed;
PRINT("\nChanged speed to ", P.getSpeed());
}
}
if (uiDirection.read() == MD_UISwitch::KEY_PRESS) // SCROLL DIRECTION
{
PRINTS("\nChanging scroll direction");
scrollEffect = (scrollEffect == PA_SCROLL_LEFT ? PA_SCROLL_RIGHT : PA_SCROLL_LEFT);
P.setTextEffect(scrollEffect, scrollEffect);
P.displayClear();
P.displayReset();
}
if (uiInvert.read() == MD_UISwitch::KEY_PRESS) // INVERT MODE
{
PRINTS("\nChanging invert mode");
P.setInvert(!P.getInvert());
}
}
#endif // USE_UI_CONTROL
void readSerial(void)
{
static char *cp = newMessage;
while (Serial.available())
{
*cp = (char)Serial.read();
if ((*cp == '\n') || (cp - newMessage >= BUF_SIZE-2)) // end of message character or full buffer
{
*cp = '\0'; // end the string
// restart the index for next filling spree and flag we have a message waiting
cp = newMessage;
newMessageAvailable = true;
}
else // move char pointer to next position
cp++;
}
}
void setup()
{
Serial.begin(115200);
Serial.print("\n[Parola_Scrolling_Example_Modified.ino]\nType a message for the scrolling display\nEnd message line with a newline");
#if USE_UI_CONTROL
uiDirection.begin();
uiInvert.begin();
pinMode(SPEED_IN, INPUT);
doUI();
#endif // USE_UI_CONTROL
P.begin();
// To reverse the scrolling direction:P.displayScroll("text", PA_LEFT, PA_SCROLL_RIGHT, 100);
scrollEffect = PA_SCROLL_RIGHT;
P.displayText(curMessage, scrollAlign, scrollSpeed, scrollPause, scrollEffect, scrollEffect);
P.setZoneEffect(0, true, PA_FLIP_UD);
P.setZoneEffect(0, true, PA_FLIP_LR);
}
void loop()
{
#if USE_UI_CONTROL
doUI();
#endif // USE_UI_CONTROL
if (P.displayAnimate())
{
if (newMessageAvailable)
{
strcpy(curMessage, newMessage);
newMessageAvailable = false;
}
P.displayReset();
}
readSerial();
}