Hi Cristian,

Mine too is almost the same design,except that I have used a 26 bit RFID cards and I also have a RTC and 2 Line LCD

Your code is less than 2K...coooooooooooool

"I can erase randomly a card from database in 25 ms or the entire data base in cca. 20 sec"

Well I have not given this feature in this unit...I will have to erase all the records and upload the records to erase 1 record :-(...Now I'll need to change this...

After reading everyone's suggestions,Now I am reading the RTC registers once every 200 milli sec(timer2 is set for 50 milli sec).once read the data are updated in the RAM(AT89c52) and from there it is updatedon the LCD.

I am always using random read/write.
What's the time gap between two random read's that you people use.

Rgds
Raj Shetgar