这个不太明白？谁能教教我？

nsl

C:\Users\ADMINI~1\AppData\Local\Temp\arduino_modified_sketch_6473\sketch_mar29d.ino: In function 'void draw()':

sketch_mar29d:62: error: 'u8g' was not declared in this scope

   u8g.drawXBMP( 0, 0, u8g_logo_width, u8g_logo_height, u8g_logo_bits);

   ^

C:\Users\ADMINI~1\AppData\Local\Temp\arduino_modified_sketch_6473\sketch_mar29d.ino: In function 'void loop()':

sketch_mar29d:72: error: 'u8g' was not declared in this scope

   u8g.firstPage();  

   ^

exit status 1
'u8g' was not declared in this scope

zjz5717

u8g没有定义