Hello Prahlad,
I have tried using the DS1232 with a P89C51RD2, but the watch dog timer was interfering, thats what I think, while trying to download code using FlashMagic or WINisp, the watch dog timer in the DS1232 cannot be disabled. I have installed an 8pin base for the DS1232 and temporarily remove the DS1232 while developing code and insert it for the production pieces.

In the current design, I am trying to remove the DS1232 and use the MCP810 in its place the MCP810 is also much smaller (SOT23).

Regards,
John.