GLCD works after reset Arduino !!!

Other Hardware Displays
1

Hello every body.
I have a mega 2560 (CH340) , DHT11 , DHT22 , Data logger shield (SD card & DS1307) , keys , LED's and GLCD (ks0108).

problem:
When I connect 12V dc power to arduino , everything work very very good except GLCD.
for example DHT send data to serial monitor or led's and keys work but GLCD don't show anything , It showing content after once or twice reset arduino with reset key on board.

I use U8g2 library for LCD.

Thanks for your advise.
TOMCAT.

2

Excuse me , I forget send my Code.

s9.1.1.ino (36.9 KB)