Hi, After power-on, the x86 processor is placed in real mode. That means the CPU looks for the instruction at the address 0xffff0. Is it correct? In SC1200 datasheet, it is given that, "Approximately 150 to 250 external clock cycles after RESET is deasserted, the processor begins executing instructions at the top of physical memory (address location FFFFFFF0h). The actual number of clock cycles depends on the clock scaling in use. Also, before execution begins, an additional 220 clock cycles are needed when self-test is requested. Typically, an intersegment jump is placed at FFFFFFF0h. This instruction will force the processor to begin execution in the lowest 1 MB of address space." In real mode, the CPU can address only 1 MB. Then how this address could be addressed by the CPU? To which address does my Flash memory gets mapped to at power-on?
_________________________________________________________________ Dont miss out on jobs that are not advertised. http://go.msnserver.com/IN/38902.asp Post your CV on naukri.com today.