i made a programmable up counter led display that counts digit from 000-999 seconds. We can set individual digits.

Hardware contains a memory.

Using 89s51 when i turn the display ON : it shows any no. randomly from 000-999 on startup.
It should actually show the last set number.
Rest everything works fine in program we can set digits and start the timer with start button.

Using 89c51 :program works absolutely fine. The memory shows the last set number .

I tried different memory ICs but problem stays. But the same program with memory works fine with 89c51.

5V supplied to controller

Memory :24c08

Crystal: 11.059Mhz

Thanks for replies