Since Keil (as opposed to some other compilers) do not supply the library in source, I have a question: I am tasked with debugging some glitches in a very strange design: External memory is used and ALE is disabled. To access external RAM one must latch the low address in an external latch by toggling a p1 pin before executing external RAM access (movx). My question thus is: do the routines in C51S EVER execute movx. I have no possibility of replacing thousands of hardware units, and already have the next version concept so I need the above question answered. Thanks in advance Erik
Actually it will access external memory, if the address is outside the internal memory range. As an example, any address above 0100H will generate an external memory access. Since the ALE is disabled on your chip, I don't know if this disables the addressing as well, but the compiler will generate code to access external memory.