I am trying to get 4 OLED screens working. I have connected them correctly (I think), and have taken a code from an library example. However, I am still getting a weird white screen.
I have connected the screens up like this:
VDD -> +5V
GND -> GND
SCK -> 21
SDA -> 20
I am using an arduino Mega2560. The code I am using looks like this:
#include <SPI.h>
#include <Wire.h>
#include <Adafruit_GFX.h>
#include <Adafruit_SSD1306.h>
#define SCREEN_WIDTH 128 // OLED display width, in pixels
#define SCREEN_HEIGHT 64 // OLED display height, in pixels
// Declaration for an SSD1306 display connected to I2C (SDA, SCL pins)
#define OLED_RESET -1 // Reset pin # (or -1 if sharing Arduino reset pin)
Adafruit_SSD1306 display(SCREEN_WIDTH, SCREEN_HEIGHT, &Wire, OLED_RESET);
#define NUMFLAKES 10 // Number of snowflakes in the animation example
#define LOGO_HEIGHT 16
#define LOGO_WIDTH 16
static const unsigned char PROGMEM logo_bmp[] =
{ B00000000, B11000000,
B00000001, B11000000,
B00000001, B11000000,
B00000011, B11100000,
B11110011, B11100000,
B11111110, B11111000,
B01111110, B11111111,
B00110011, B10011111,
B00011111, B11111100,
B00001101, B01110000,
B00011011, B10100000,
B00111111, B11100000,
B00111111, B11110000,
B01111100, B11110000,
B01110000, B01110000,
B00000000, B00110000 };
void setup() {
Serial.begin(115200);
// SSD1306_SWITCHCAPVCC = generate display voltage from 3.3V internally
if(!display.begin(SSD1306_SWITCHCAPVCC, 0x3C)) {
Serial.println(F("SSD1306 allocation failed"));
for(;;); // Don't proceed, loop forever
}
// Show initial display buffer contents on the screen --
// the library initializes this with an Adafruit splash screen.
display.display();
delay(2000); // Pause for 2 seconds
// Clear the buffer
display.clearDisplay();
// Draw a single pixel in white
display.drawPixel(10, 10, WHITE);
// Show the display buffer on the screen. You MUST call display() after
// drawing commands to make them visible on screen!
display.display();
delay(2000);
// display.display() is NOT necessary after every single drawing command,
// unless that's what you want...rather, you can batch up a bunch of
// drawing operations and then update the screen all at once by calling
// display.display(). These examples demonstrate both approaches...
testdrawline(); // Draw many lines
testdrawrect(); // Draw rectangles (outlines)
testfillrect(); // Draw rectangles (filled)
testdrawcircle(); // Draw circles (outlines)
testfillcircle(); // Draw circles (filled)
testdrawroundrect(); // Draw rounded rectangles (outlines)
testfillroundrect(); // Draw rounded rectangles (filled)
testdrawtriangle(); // Draw triangles (outlines)
testfilltriangle(); // Draw triangles (filled)
testdrawchar(); // Draw characters of the default font
testdrawstyles(); // Draw 'stylized' characters
testscrolltext(); // Draw scrolling text
testdrawbitmap(); // Draw a small bitmap image
// Invert and restore display, pausing in-between
display.invertDisplay(true);
delay(1000);
display.invertDisplay(false);
delay(1000);
testanimate(logo_bmp, LOGO_WIDTH, LOGO_HEIGHT); // Animate bitmaps
}
void loop() {
}
void testdrawline() {
int16_t i;
display.clearDisplay(); // Clear display buffer
for(i=0; i<display.width(); i+=4) {
display.drawLine(0, 0, i, display.height()-1, WHITE);
display.display(); // Update screen with each newly-drawn line
delay(1);
}
for(i=0; i<display.height(); i+=4) {
display.drawLine(0, 0, display.width()-1, i, WHITE);
display.display();
delay(1);
}
delay(250);
display.clearDisplay();
for(i=0; i<display.width(); i+=4) {
display.drawLine(0, display.height()-1, i, 0, WHITE);
display.display();
delay(1);
}
for(i=display.height()-1; i>=0; i-=4) {
display.drawLine(0, display.height()-1, display.width()-1, i, WHITE);
display.display();
delay(1);
}
delay(250);
display.clearDisplay();
for(i=display.width()-1; i>=0; i-=4) {
display.drawLine(display.width()-1, display.height()-1, i, 0, WHITE);
display.display();
delay(1);
}
for(i=display.height()-1; i>=0; i-=4) {
display.drawLine(display.width()-1, display.height()-1, 0, i, WHITE);
display.display();
delay(1);
}
delay(250);
display.clearDisplay();
for(i=0; i<display.height(); i+=4) {
display.drawLine(display.width()-1, 0, 0, i, WHITE);
display.display();
delay(1);
}
for(i=0; i<display.width(); i+=4) {
display.drawLine(display.width()-1, 0, i, display.height()-1, WHITE);
display.display();
delay(1);
}
delay(2000); // Pause for 2 seconds
}
void testdrawrect(void) {
display.clearDisplay();
for(int16_t i=0; i<display.height()/2; i+=2) {
display.drawRect(i, i, display.width()-2*i, display.height()-2*i, WHITE);
display.display(); // Update screen with each newly-drawn rectangle
delay(1);
}
delay(2000);
}
void testfillrect(void) {
display.clearDisplay();
for(int16_t i=0; i<display.height()/2; i+=3) {
// The INVERSE color is used so rectangles alternate white/black
display.fillRect(i, i, display.width()-i*2, display.height()-i*2, INVERSE);
display.display(); // Update screen with each newly-drawn rectangle
delay(1);
}
delay(2000);
}
void testdrawcircle(void) {
display.clearDisplay();
for(int16_t i=0; i<max(display.width(),display.height())/2; i+=2) {
display.drawCircle(display.width()/2, display.height()/2, i, WHITE);
display.display();
delay(1);
}
delay(2000);
}
void testfillcircle(void) {
display.clearDisplay();
for(int16_t i=max(display.width(),display.height())/2; i>0; i-=3) {
// The INVERSE color is used so circles alternate white/black
display.fillCircle(display.width() / 2, display.height() / 2, i, INVERSE);
display.display(); // Update screen with each newly-drawn circle
delay(1);
}
delay(2000);
}
void testdrawroundrect(void) {
display.clearDisplay();
for(int16_t i=0; i<display.height()/2-2; i+=2) {
display.drawRoundRect(i, i, display.width()-2*i, display.height()-2*i,
display.height()/4, WHITE);
display.display();
delay(1);
}
delay(2000);
}
void testfillroundrect(void) {
display.clearDisplay();
for(int16_t i=0; i<display.height()/2-2; i+=2) {
// The INVERSE color is used so round-rects alternate white/black
display.fillRoundRect(i, i, display.width()-2*i, display.height()-2*i,
display.height()/4, INVERSE);
display.display();
delay(1);
}
delay(2000);
}
void testdrawtriangle(void) {
display.clearDisplay();
for(int16_t i=0; i<max(display.width(),display.height())/2; i+=5) {
display.drawTriangle(
display.width()/2 , display.height()/2-i,
display.width()/2-i, display.height()/2+i,
display.width()/2+i, display.height()/2+i, WHITE);
display.display();
delay(1);
}
delay(2000);
}
void testfilltriangle(void) {
display.clearDisplay();
for(int16_t i=max(display.width(),display.height())/2; i>0; i-=5) {
// The INVERSE color is used so triangles alternate white/black
display.fillTriangle(
display.width()/2 , display.height()/2-i,
display.width()/2-i, display.height()/2+i,
display.width()/2+i, display.height()/2+i, INVERSE);
display.display();
delay(1);
}
delay(2000);
}
void testdrawchar(void) {
display.clearDisplay();
display.setTextSize(1); // Normal 1:1 pixel scale
display.setTextColor(WHITE); // Draw white text
display.setCursor(0, 0); // Start at top-left corner
display.cp437(true); // Use full 256 char 'Code Page 437' font
// Not all the characters will fit on the display. This is normal.
// Library will draw what it can and the rest will be clipped.
for(int16_t i=0; i<256; i++) {
if(i == 'n') display.write(' ');
else display.write(i);
}
display.display();
delay(2000);
}
void testdrawstyles(void) {
display.clearDisplay();
display.setTextSize(1); // Normal 1:1 pixel scale
display.setTextColor(WHITE); // Draw white text
display.setCursor(0,0); // Start at top-left corner
display.println(F("Hello, world!"));
display.setTextColor(BLACK, WHITE); // Draw 'inverse' text
display.println(3.141592);
display.setTextSize(2); // Draw 2X-scale text
display.setTextColor(WHITE);
display.print(F("0x")); display.println(0xDEADBEEF, HEX);
display.display();
delay(2000);
}
void testscrolltext(void) {
display.clearDisplay();
display.setTextSize(2); // Draw 2X-scale text
display.setTextColor(WHITE);
display.setCursor(10, 0);
display.println(F("scroll"));
display.display(); // Show initial text
delay(100);
// Scroll in various directions, pausing in-between:
display.startscrollright(0x00, 0x0F);
delay(2000);
display.stopscroll();
delay(1000);
display.startscrollleft(0x00, 0x0F);
delay(2000);
display.stopscroll();
delay(1000);
display.startscrolldiagright(0x00, 0x07);
delay(2000);
display.startscrolldiagleft(0x00, 0x07);
delay(2000);
display.stopscroll();
delay(1000);
}
void testdrawbitmap(void) {
display.clearDisplay();
display.drawBitmap(
(display.width() - LOGO_WIDTH ) / 2,
(display.height() - LOGO_HEIGHT) / 2,
logo_bmp, LOGO_WIDTH, LOGO_HEIGHT, 1);
display.display();
delay(1000);
}
#define XPOS 0 // Indexes into the 'icons' array in function below
#define YPOS 1
#define DELTAY 2
void testanimate(const uint8_t *bitmap, uint8_t w, uint8_t h) {
int8_t f, icons[NUMFLAKES][3];
// Initialize 'snowflake' positions
for(f=0; f< NUMFLAKES; f++) {
icons[f][XPOS] = random(1 - LOGO_WIDTH, display.width());
icons[f][YPOS] = -LOGO_HEIGHT;
icons[f][DELTAY] = random(1, 6);
Serial.print(F("x: "));
Serial.print(icons[f][XPOS], DEC);
Serial.print(F(" y: "));
Serial.print(icons[f][YPOS], DEC);
Serial.print(F(" dy: "));
Serial.println(icons[f][DELTAY], DEC);
}
for(;;) { // Loop forever...
display.clearDisplay(); // Clear the display buffer
// Draw each snowflake:
for(f=0; f< NUMFLAKES; f++) {
display.drawBitmap(icons[f][XPOS], icons[f][YPOS], bitmap, w, h, WHITE);
}
display.display(); // Show the display buffer on the screen
delay(200); // Pause for 1/10 second
// Then update coordinates of each flake...
for(f=0; f< NUMFLAKES; f++) {
icons[f][YPOS] += icons[f][DELTAY];
// If snowflake is off the bottom of the screen...
if (icons[f][YPOS] >= display.height()) {
// Reinitialize to a random position, just off the top
icons[f][XPOS] = random(1 - LOGO_WIDTH, display.width());
icons[f][YPOS] = -LOGO_HEIGHT;
icons[f][DELTAY] = random(1, 6);
}
}
}
}
This is an example from one of the librarys I am using so I don’t understand it well enough to effectivly know whats wrong/what could be wrong. Not sure where the addresses are on the actual OLEDs.