Works on Uno, but not on Mega

Other Hardware Displays
1

Hi,

I am having abit of trouble and more than likely not understanding.

I am looking to put an image through the mega, 64*64 in size.

Its a SSD1351 colour OLED.

This code outputs fine on the Uno, but would display anything on the Mega.

//included libraries
#include "SPI.h" //Includes library for SPI communication of display
#include "Adafruit_GFX.h" //Includes core graphics library
#include "Adafruit_SSD1351.h" //Includes hardware specific library

extern const uint16_t smiley48[];

//screen dimensions
#define SCREEN_WIDTH 128 //pixel width
#define SCREEN_HEIGHT 128 //pixel height

//pin definitions
#define SCLK_PIN 13 //defines s clock pin
#define MOSI_PIN 11 //defines master-out slave-in SDA pin
#define RST_PIN   3 //defines reset pin
#define DC_PIN    5 //defines master-in slave-out pin
#define CS_PIN    4 //defines chip select pin

// Colour definitions
#define BLACK           0x0000
#define BLUE            0x001F
#define RED             0xF800
#define GREEN           0x07E0
#define CYAN            0x07FF
#define MAGENTA         0xF81F
#define YELLOW          0xFFE0  
#define WHITE           0xFFFF
#define GREY            0x8410
#define ORANGE          0xE880

Adafruit_SSD1351 display = Adafruit_SSD1351(SCREEN_WIDTH, SCREEN_HEIGHT, &SPI, CS_PIN, DC_PIN, RST_PIN);

void setup() {
  display.begin();
  display.fillScreen(BLACK);
}

void loop() {
  display.drawRGBBitmap(0,0,smiley48,64,64);
  delay(1000);
}
2 
#define SCLK_PIN 13 //defines s clock pin
#define MOSI_PIN 11 //defines master-out slave-in SDA pin

These are the wrong pins for SPI on a Mega

3

I can get the test file to output on the following, but still no image.

#define SCLK_PIN 21
#define MOSI_PIN 20
#define DC_PIN 50
#define CS_PIN 52
#define RST_PIN 48
4

Post the schematic

5

Why did you selected these pins?
Look at the manual:

SPI uses the SCK, MOSI, MISO and CS (or SS) pins. Those pins are 52, 51, 50 and 53 (defalut) on a Mega.

6

I have run it on the 50s and the 20s, but only the SSD1351 test file.
When i try the above code, which works on Uno, no image is displayed.
I dont have any information on the screen except what is supplied here:

7

Be sure to use the SPI pins that are correct for the MCU you are using. Double check the wiring.

8

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