#define EXT_I2C_SDA 21
#define EXT_I2C_SCL 5

const int extCenterX = 64;
const int extCenterY = -70;

void initExtDisplay();
void pixelOnExtDisplay(int16_t x, int16_t y);
void lineCalcOnExtDisplay(int16_t x, int16_t y, int radius);
void overlayOnExtDisplay();
float valueOnExtDisplay(float value);
void drawLineExtDisplay(float value);
void changeExt(float value);