20X4 LCD Problem

@ Ajay Sir

I have downloaded the LCD interfacing source code(4 wire program) from this forum and run it on 20X4 alphanumeric LCD, its all ok but some time the display got disturbed like it shows some garbage data like chinese words and some times LCD's 2nd and 4th line got dark and 1st and 3rd line clears but at this time controller operates as its normal operation i,e. internally controller do execution for LCD but LCD dont shows it.
I could't understand whether it is software problem or hardware problem.

Because it goes normal by power reset not by controller reset.

Please reply.

Thanks in advance

There can be two reasons for this that I can think of:
1. Unstable power supply
2. If no read/write pin is used then increase of delay needed after each command/data write

@ Ajay sir
May be there is power supply problem i try to smoothen the voltage.
One more thing, here read/write pin is permanently at ground and the data pins D0, D1, D2 and D3 are open.
Should I have to ground these pin, could these pins are cause of problem.

Thank you

yes you should better ground D0 to D3 if not used. When LCD is powered on it is by default in 8-bit mode and any noise on these data lines may cause your LCD to behave abnormal.