Hi All H/W system has: 1) 89C51RD2 (MC) 2) DS1232 as system reset IC ( Resets sys,if its strobe pin in not toggled in 1.2 Sec). In normal execution mode 1 port pin of MC toggles strobe pin of DS1232 before 1.2 Sec expires. ISP feature of 89C51RD2 is to be used for loading hex file in its flash. Since strobe pin is not toggled in ISP mode,DS1232 keeps on resetting system. and hence ISP is not able to load hex file. Sorry to say that this problem is not related to keil. can anybody provide way out of this if any one who have faced this problem. rgds Naresh