Connecting 128x4 LCD to arduino Nano

Use the u8glib library hello world to verify the code and following should be the constructor. 

Constructor used: 

U8GLIB_ST7920_128X64 u8g(4, 3, 2, U8G_PIN_NONE); 

or 

U8GLIB_ST7920_128X64 u8g(A0, A1, A2, U8G_PIN_NONE); 

1 -> Gnd 

2 -> Vcc 

4(RS) -> A2/D2 

5(R/W) -> A1/D3 

6(E) -> A0/D4 

19 -> Vcc 

20 -> Gnd 

 Troubleshooting: 

1. LCD doesn't show the characters even after connecting the nano and verifying the code on uno.       

 Solution: I used Vin pin of the nano to power the lcd, it should have been 5v pin instead.