Adafruit SSD1306, I2C, ATmega1284p: Pantalla OLED torcida / desalineada

Otro problema extraño aquí. La configuración:

La placa OLED Adafruit SSD1306 está conectada a un ATMega1284p a través de I2C.

Ya que "aumenté" mi 1284 a 8MHz (lo que necesitaba para hablar de manera confiable con mis sensores de temperatura a través de OneWire), la pantalla es "akew" o "desalineada" (ver más abajo) de manera que la "coordenada cero" (lo que yo llamaría el comienzo de la pantalla) ya no está en la parte superior, sino más bien en un cuarto de pantalla hacia abajo (aproximadamente en la línea roja):

CarguéelbosquejodeejemplosinmodificarparaelSSD1306deAdafruitquefuncionabiena1MHzenel1284oa16MHzusandolaplacaDuemilanove.

¿Algunaideasobrequépodríahacerquelapantallase"mueva hacia abajo" de tal manera?

¡Gracias!

El código (ejemplo de boceto no modificado, solo el pin de reinicio se mueve al pin 21 (esto funciona bien a 1MHz), es decir, la línea #define OLED_RESET 21 generalmente es #define OLED_RESET 4 ):

/*********************************************************************
This is an example for our Monochrome OLEDs based on SSD1306 drivers

  Pick one up today in the adafruit shop!
  ------> http://www.adafruit.com/category/63_98

This example is for a 128x64 size display using I2C to communicate
3 pins are required to interface (2 I2C and one reset)

Adafruit invests time and resources providing this open source code, 
please support Adafruit and open-source hardware by purchasing 
products from Adafruit!

Written by Limor Fried/Ladyada  for Adafruit Industries.  
BSD license, check license.txt for more information
All text above, and the splash screen must be included in any redistribution
*********************************************************************/

#include <Wire.h>
#include <Adafruit_GFX.h>
#include <Adafruit_SSD1306.h>

#define OLED_RESET 21
Adafruit_SSD1306 display(OLED_RESET);

#define NUMFLAKES 10
#define XPOS 0
#define YPOS 1
#define DELTAY 2


#define LOGO16_GLCD_HEIGHT 16 
#define LOGO16_GLCD_WIDTH  16 
static unsigned char PROGMEM logo16_glcd_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 };

#if (SSD1306_LCDHEIGHT != 64)
#error("Height incorrect, please fix Adafruit_SSD1306.h!");
#endif

void setup()   {                
  Serial.begin(9600);

  // by default, we'll generate the high voltage from the 3.3v line internally! (neat!)
  display.begin(SSD1306_SWITCHCAPVCC, 0x3D);  // initialize with the I2C addr 0x3D (for the 128x64)
  // init done

  display.display(); // show splashscreen
  delay(2000);
  display.clearDisplay();   // clears the screen and buffer

  // draw a single pixel
  display.drawPixel(10, 10, WHITE);
  display.display();
  delay(2000);
  display.clearDisplay();

  // draw many lines
  testdrawline();
  display.display();
  delay(2000);
  display.clearDisplay();

  // draw rectangles
  testdrawrect();
  display.display();
  delay(2000);
  display.clearDisplay();

  // draw multiple rectangles
  testfillrect();
  display.display();
  delay(2000);
  display.clearDisplay();

  // draw mulitple circles
  testdrawcircle();
  display.display();
  delay(2000);
  display.clearDisplay();

  // draw a white circle, 10 pixel radius
  display.fillCircle(display.width()/2, display.height()/2, 10, WHITE);
  display.display();
  delay(2000);
  display.clearDisplay();

  testdrawroundrect();
  delay(2000);
  display.clearDisplay();

  testfillroundrect();
  delay(2000);
  display.clearDisplay();

  testdrawtriangle();
  delay(2000);
  display.clearDisplay();

  testfilltriangle();
  delay(2000);
  display.clearDisplay();

  // draw the first ~12 characters in the font
  testdrawchar();
  display.display();
  delay(2000);
  display.clearDisplay();

  // draw scrolling text
  testscrolltext();
  delay(2000);
  display.clearDisplay();

  // text display tests
  display.setTextSize(1);
  display.setTextColor(WHITE);
  display.setCursor(0,0);
  display.println("Hello, world!");
  display.setTextColor(BLACK, WHITE); // 'inverted' text
  display.println(3.141592);
  display.setTextSize(2);
  display.setTextColor(WHITE);
  display.print("0x"); display.println(0xDEADBEEF, HEX);
  display.display();
  delay(2000);

  // miniature bitmap display
  display.clearDisplay();
  display.drawBitmap(30, 16,  logo16_glcd_bmp, 16, 16, 1);
  display.display();

  // invert the display
  display.invertDisplay(true);
  delay(1000); 
  display.invertDisplay(false);
  delay(1000); 

  // draw a bitmap icon and 'animate' movement
  testdrawbitmap(logo16_glcd_bmp, LOGO16_GLCD_HEIGHT, LOGO16_GLCD_WIDTH);
}


void loop() {

}


void testdrawbitmap(const uint8_t *bitmap, uint8_t w, uint8_t h) {
  uint8_t icons[NUMFLAKES][3];
  srandom(666);     // whatever seed

  // initialize
  for (uint8_t f=0; f< NUMFLAKES; f++) {
    icons[f][XPOS] = random() % display.width();
    icons[f][YPOS] = 0;
    icons[f][DELTAY] = random() % 5 + 1;

    Serial.print("x: ");
    Serial.print(icons[f][XPOS], DEC);
    Serial.print(" y: ");
    Serial.print(icons[f][YPOS], DEC);
    Serial.print(" dy: ");
    Serial.println(icons[f][DELTAY], DEC);
  }

  while (1) {
    // draw each icon
    for (uint8_t f=0; f< NUMFLAKES; f++) {
      display.drawBitmap(icons[f][XPOS], icons[f][YPOS], logo16_glcd_bmp, w, h, WHITE);
    }
    display.display();
    delay(200);

    // then erase it + move it
    for (uint8_t f=0; f< NUMFLAKES; f++) {
      display.drawBitmap(icons[f][XPOS], icons[f][YPOS],  logo16_glcd_bmp, w, h, BLACK);
      // move it
      icons[f][YPOS] += icons[f][DELTAY];
      // if its gone, reinit
      if (icons[f][YPOS] > display.height()) {
    icons[f][XPOS] = random() % display.width();
    icons[f][YPOS] = 0;
    icons[f][DELTAY] = random() % 5 + 1;
      }
    }
   }
}


void testdrawchar(void) {
  display.setTextSize(1);
  display.setTextColor(WHITE);
  display.setCursor(0,0);

  for (uint8_t i=0; i < 168; i++) {
    if (i == '\n') continue;
    display.write(i);
    if ((i > 0) && (i % 21 == 0))
      display.println();
  }    
  display.display();
}

void testdrawcircle(void) {
  for (int16_t i=0; i<display.height(); i+=2) {
    display.drawCircle(display.width()/2, display.height()/2, i, WHITE);
    display.display();
  }
}

void testfillrect(void) {
  uint8_t color = 1;
  for (int16_t i=0; i<display.height()/2; i+=3) {
    // alternate colors
    display.fillRect(i, i, display.width()-i*2, display.height()-i*2, color%2);
    display.display();
    color++;
  }
}

void testdrawtriangle(void) {
  for (int16_t i=0; i<min(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();
  }
}

void testfilltriangle(void) {
  uint8_t color = WHITE;
  for (int16_t i=min(display.width(),display.height())/2; i>0; i-=5) {
    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, WHITE);
    if (color == WHITE) color = BLACK;
    else color = WHITE;
    display.display();
  }
}

void testdrawroundrect(void) {
  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();
  }
}

void testfillroundrect(void) {
  uint8_t color = WHITE;
  for (int16_t i=0; i<display.height()/2-2; i+=2) {
    display.fillRoundRect(i, i, display.width()-2*i, display.height()-2*i, display.height()/4, color);
    if (color == WHITE) color = BLACK;
    else color = WHITE;
    display.display();
  }
}

void testdrawrect(void) {
  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();
  }
}

void testdrawline() {  
  for (int16_t i=0; i<display.width(); i+=4) {
    display.drawLine(0, 0, i, display.height()-1, WHITE);
    display.display();
  }
  for (int16_t i=0; i<display.height(); i+=4) {
    display.drawLine(0, 0, display.width()-1, i, WHITE);
    display.display();
  }
  delay(250);

  display.clearDisplay();
  for (int16_t i=0; i<display.width(); i+=4) {
    display.drawLine(0, display.height()-1, i, 0, WHITE);
    display.display();
  }
  for (int16_t i=display.height()-1; i>=0; i-=4) {
    display.drawLine(0, display.height()-1, display.width()-1, i, WHITE);
    display.display();
  }
  delay(250);

  display.clearDisplay();
  for (int16_t i=display.width()-1; i>=0; i-=4) {
    display.drawLine(display.width()-1, display.height()-1, i, 0, WHITE);
    display.display();
  }
  for (int16_t i=display.height()-1; i>=0; i-=4) {
    display.drawLine(display.width()-1, display.height()-1, 0, i, WHITE);
    display.display();
  }
  delay(250);

  display.clearDisplay();
  for (int16_t i=0; i<display.height(); i+=4) {
    display.drawLine(display.width()-1, 0, 0, i, WHITE);
    display.display();
  }
  for (int16_t i=0; i<display.width(); i+=4) {
    display.drawLine(display.width()-1, 0, i, display.height()-1, WHITE); 
    display.display();
  }
  delay(250);
}

void testscrolltext(void) {
  display.setTextSize(2);
  display.setTextColor(WHITE);
  display.setCursor(10,0);
  display.clearDisplay();
  display.println("scroll");
  display.display();

  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();
}