I found an interesting thing.I am using a JHD162A 16*2 LCD based on HD44780 architecture. Now in my simulation I am using LM016L LCD module that was previously working in 130kHz frequency. As soon as I changed the frequency to 3Mhz and the simulation jump-started to work perfectly. But coming to the main part, I could change the frequency of the LCD simulation but what about the hardware? can you tell how I can change the working frequency of LCD display so that it can work in sync with the MCU??