Success! After I change the loop part back to:
void loop() {
u8g2.firstPage();
/*u8g2.clearBuffer(); */
do {
u8g2.drawStr(30, 12.8, line1);
u8g2.drawStr(30, 25.6, line2);
u8g2.drawStr(30, 38.4, line3);
u8g2.drawStr(30, 51.2, line4);
u8g2.drawStr(30, 64, line5);
} while ( u8g2.nextPage() );
u8g2.updateDisplay();
/*u8g2.sendBuffer();*/
DcsBios::loop();
}
The DED display correct now! But the invert texts looks like still wip and the refresh speed is slow. The DED is working well now but I'd like to know if there are any way to increase the refresh speed. Thanks for you all to create this sketch!