Revisions to Problems with Draw Loop using u8glib

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edit approved Nov 27, 2015 at 17:09

dda

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I am using aan Arduino Mega and a 12864ZW LCD usingwith the u8glib library and the following code to draw to the LCD:

U8GLIB_ST7920_128X64 Display(LCD_E_PIN, LCD_RW_PIN, LCD_RS_PIN, U8G_PIN_NONE);

void loop(){
   Draw();
}

void Draw(){
   Display.firstPage();

   do{
      Display.setPrintPos(10, 10);
      Display.print("This is a test");
   }while(Display.nextPage());
}

The problem is that the Displaydisplay is constantly redrawing itself. When I have used LCD Displaysdisplays in the past it is, they usually only required to write to the LCD once unless you wipe the display. When I adjusted the code to:

U8GLIB_ST7920_128X64 Display(LCD_E_PIN, LCD_RW_PIN, LCD_RS_PIN, U8G_PIN_NONE);
bool needsUpdate = true;

void loop(){
   Draw();
}

void Draw(){
 
   if (needsUpdate){
 
       Display.firstPage();
 
       do{
          Display.setPrintPos(10, 10);
          Display.print("This is a test");
       }while(Display.nextPage());
       
       needsUpdate = false;
   }
}

I do not get anything drawn on the LCD. Is there a parameter that needs to be set so I only have to redraw the LCD if something changes? Am I using aan outdated library? Is there a better library I should be using?

EDIT

I think the main problem I have with using this library is does the Draw loop need to be executed continuously to display on the LCD or is there a way to only draw the screen once until it is needed to be drawn again?

I am using a Arduino Mega and a 12864ZW LCD using the u8glib and the following code to draw to the LCD:

U8GLIB_ST7920_128X64 Display(LCD_E_PIN, LCD_RW_PIN, LCD_RS_PIN, U8G_PIN_NONE);

void loop(){
   Draw();
}

void Draw(){
   Display.firstPage();

   do{
      Display.setPrintPos(10, 10);
      Display.print("This is a test");
   }while(Display.nextPage());
}

The problem is the Display is constantly redrawing itself. When I have used LCD Displays in the past it is usually only required to write to the LCD once unless you wipe the display. When I adjusted the code to:

U8GLIB_ST7920_128X64 Display(LCD_E_PIN, LCD_RW_PIN, LCD_RS_PIN, U8G_PIN_NONE);
bool needsUpdate = true;

void loop(){
   Draw();
}

void Draw(){
 
   if (needsUpdate){
 
       Display.firstPage();
 
       do{
          Display.setPrintPos(10, 10);
          Display.print("This is a test");
       }while(Display.nextPage());
       
       needsUpdate = false;
   }
}

I do not get anything drawn on the LCD. Is there a parameter that needs to be set so I only have to redraw the LCD if something changes? Am I using a outdated library? Is there a better library I should be using?

EDIT

I think the main problem I have with using this library is does the Draw loop need to be executed continuously to display on the LCD or is there a way to only draw the screen once until it is needed to be drawn again?

I am using an Arduino Mega and a 12864ZW LCD with the u8glib library and the following code to draw to the LCD:

U8GLIB_ST7920_128X64 Display(LCD_E_PIN, LCD_RW_PIN, LCD_RS_PIN, U8G_PIN_NONE);

void loop(){
   Draw();
}

void Draw(){
   Display.firstPage();

   do{
      Display.setPrintPos(10, 10);
      Display.print("This is a test");
   }while(Display.nextPage());
}

The problem is that the display is constantly redrawing itself. When I used LCD displays in the past, they usually only required to write to the LCD once unless you wipe the display. When I adjusted the code to:

U8GLIB_ST7920_128X64 Display(LCD_E_PIN, LCD_RW_PIN, LCD_RS_PIN, U8G_PIN_NONE);
bool needsUpdate = true;

void loop(){
   Draw();
}

void Draw(){
   if (needsUpdate){
       Display.firstPage();
       do{
          Display.setPrintPos(10, 10);
          Display.print("This is a test");
       }while(Display.nextPage());
       needsUpdate = false;
   }
}

I do not get anything drawn on the LCD. Is there a parameter that needs to be set so I only have to redraw the LCD if something changes? Am I using an outdated library? Is there a better library I should be using?

EDIT

I think the main problem I have with using this library is does the Draw loop need to be executed continuously to display on the LCD or is there a way to only draw the screen once until it is needed to be drawn again?

added 237 characters in body

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edited Nov 26, 2015 at 20:15

Andy Braham

468
1
8
17

I am using a Arduino Mega and a 12864ZW LCD using the u8glib and the following code to draw to the LCD:

U8GLIB_ST7920_128X64 Display(LCD_E_PIN, LCD_RW_PIN, LCD_RS_PIN, U8G_PIN_NONE);

void loop(){
   Draw();
}

void Draw(){
   Display.firstPage();

   do{
      Display.setPrintPos(10, 10);
      Display.print("This is a test");
   }while(Display.nextPage());
}

The problem is the Display is constantly redrawing itself. When I have used LCD Displays in the past it is usually only required to write to the LCD once unless you wipe the display. When I adjusted the code to:

U8GLIB_ST7920_128X64 Display(LCD_E_PIN, LCD_RW_PIN, LCD_RS_PIN, U8G_PIN_NONE);
bool needsUpdate = true;

void loop(){
   Draw();
}

void Draw(){

   if (needsUpdate){

       Display.firstPage();

       do{
          Display.setPrintPos(10, 10);
          Display.print("This is a test");
       }while(Display.nextPage());
       
       needsUpdate = false;
   }
}

I do not get anything drawn on the LCD. Is there a parameter that needs to be set so I only have to redraw the LCD if something changes? Am I using a outdated library? Is there a better library I should be using?

EDIT

I think the main problem I have with using this library is does the Draw loop need to be executed continuously to display on the LCD or is there a way to only draw the screen once until it is needed to be drawn again?

I am using a Arduino Mega and a 12864ZW LCD using the u8glib and the following code to draw to the LCD:

U8GLIB_ST7920_128X64 Display(LCD_E_PIN, LCD_RW_PIN, LCD_RS_PIN, U8G_PIN_NONE);

void loop(){
   Draw();
}

void Draw(){
   Display.firstPage();

   do{
      Display.setPrintPos(10, 10);
      Display.print("This is a test");
   }while(Display.nextPage());
}

The problem is the Display is constantly redrawing itself. When I have used LCD Displays in the past it is usually only required to write to the LCD once unless you wipe the display. When I adjusted the code to:

U8GLIB_ST7920_128X64 Display(LCD_E_PIN, LCD_RW_PIN, LCD_RS_PIN, U8G_PIN_NONE);
bool needsUpdate = true;

void loop(){
   Draw();
}

void Draw(){

   if (needsUpdate){

       Display.firstPage();

       do{
          Display.setPrintPos(10, 10);
          Display.print("This is a test");
       }while(Display.nextPage());
       
       needsUpdate = false;
   }
}

I do not get anything drawn on the LCD. Is there a parameter that needs to be set so I only have to redraw the LCD if something changes? Am I using a outdated library? Is there a better library I should be using?

I am using a Arduino Mega and a 12864ZW LCD using the u8glib and the following code to draw to the LCD:

U8GLIB_ST7920_128X64 Display(LCD_E_PIN, LCD_RW_PIN, LCD_RS_PIN, U8G_PIN_NONE);

void loop(){
   Draw();
}

void Draw(){
   Display.firstPage();

   do{
      Display.setPrintPos(10, 10);
      Display.print("This is a test");
   }while(Display.nextPage());
}

The problem is the Display is constantly redrawing itself. When I have used LCD Displays in the past it is usually only required to write to the LCD once unless you wipe the display. When I adjusted the code to:

U8GLIB_ST7920_128X64 Display(LCD_E_PIN, LCD_RW_PIN, LCD_RS_PIN, U8G_PIN_NONE);
bool needsUpdate = true;

void loop(){
   Draw();
}

void Draw(){

   if (needsUpdate){

       Display.firstPage();

       do{
          Display.setPrintPos(10, 10);
          Display.print("This is a test");
       }while(Display.nextPage());
       
       needsUpdate = false;
   }
}

I do not get anything drawn on the LCD. Is there a parameter that needs to be set so I only have to redraw the LCD if something changes? Am I using a outdated library? Is there a better library I should be using?

EDIT

I think the main problem I have with using this library is does the Draw loop need to be executed continuously to display on the LCD or is there a way to only draw the screen once until it is needed to be drawn again?

added 86 characters in body

Source Link

edited Nov 26, 2015 at 18:52

Andy Braham

468
1
8
17

I am using a Arduino Mega and a 12864ZW LCD using the u8glib and the following code to draw to the LCD:

U8GLIB_ST7920_128X64 Display(LCD_E_PIN, LCD_RW_PIN, LCD_RS_PIN, U8G_PIN_NONE);

void loop(){
   Draw();
}

void Draw(){
   Display.firstPage();

   do{
      Display.setPrintPos(10, 10);
      Display.print("This is a test");
   }while(Display.nextPage());
}

The problem is the Display is constantly redrawing itself. When I have used LCD Displays in the past it is usually only required to write to the LCD once unless you wipe the display. When I adjusted the code to:

U8GLIB_ST7920_128X64 Display(LCD_E_PIN, LCD_RW_PIN, LCD_RS_PIN, U8G_PIN_NONE);
bool needsUpdate = true;

void Drawloop(){
   Display.firstPageDraw();
}

void Draw(){

   if (needsUpdate){

       Display.firstPage();

       do{
          Display.setPrintPos(10, 10);
          Display.print("This is a test");
       }while(Display.nextPage());
       
       needsUpdate = false;
   }
}

I do not get anything drawn on the LCD. Is there a parameter that needs to be set so I only have to redraw the LCD if something changes? Am I using a outdated library? Is there a better library I should be using?

I am using a Arduino Mega and a 12864ZW LCD using the u8glib and the following code to draw to the LCD:

U8GLIB_ST7920_128X64 Display(LCD_E_PIN, LCD_RW_PIN, LCD_RS_PIN, U8G_PIN_NONE);

void Draw(){
   Display.firstPage();

   do{
      Display.setPrintPos(10, 10);
      Display.print("This is a test");
   }while(Display.nextPage());
}

The problem is the Display is constantly redrawing itself. When I have used LCD Displays in the past it is usually only required to write to the LCD once unless you wipe the display. When I adjusted the code to:

U8GLIB_ST7920_128X64 Display(LCD_E_PIN, LCD_RW_PIN, LCD_RS_PIN, U8G_PIN_NONE);
bool needsUpdate = true;

void Draw(){
   Display.firstPage();

   if (needsUpdate){
       do{
          Display.setPrintPos(10, 10);
          Display.print("This is a test");
       }while(Display.nextPage());
       
       needsUpdate = false;
   }
}

I do not get anything drawn on the LCD. Is there a parameter that needs to be set so I only have to redraw the LCD if something changes? Am I using a outdated library? Is there a better library I should be using?

I am using a Arduino Mega and a 12864ZW LCD using the u8glib and the following code to draw to the LCD:

U8GLIB_ST7920_128X64 Display(LCD_E_PIN, LCD_RW_PIN, LCD_RS_PIN, U8G_PIN_NONE);

void loop(){
   Draw();
}

void Draw(){
   Display.firstPage();

   do{
      Display.setPrintPos(10, 10);
      Display.print("This is a test");
   }while(Display.nextPage());
}

The problem is the Display is constantly redrawing itself. When I have used LCD Displays in the past it is usually only required to write to the LCD once unless you wipe the display. When I adjusted the code to:

U8GLIB_ST7920_128X64 Display(LCD_E_PIN, LCD_RW_PIN, LCD_RS_PIN, U8G_PIN_NONE);
bool needsUpdate = true;

void loop(){
   Draw();
}

void Draw(){

   if (needsUpdate){

       Display.firstPage();

       do{
          Display.setPrintPos(10, 10);
          Display.print("This is a test");
       }while(Display.nextPage());
       
       needsUpdate = false;
   }
}

I do not get anything drawn on the LCD. Is there a parameter that needs to be set so I only have to redraw the LCD if something changes? Am I using a outdated library? Is there a better library I should be using?

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edited Nov 26, 2015 at 18:10

James Waldby - jwpat7

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asked Nov 26, 2015 at 17:55

Andy Braham

468
1
8
17

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