Internal/External Memory Questions

Sorry for the newb questions, but I can't find the answers in either the UV2 or C51 manuals.

1) When UV2 gives the Program Data Size after building a project, is this JUST data (first 128 bytes), or is idata included in this total as well? I think it is all 256 bytes, but wanted to make sure.

2) If all internal data memory is exceeded, is the data simply truncated there or is it moved to xdata or something else?

3) I understand that access to xdata is slower than for internal RAM, but is it possible to put a quantification on "slower"? I realize this is likely micro dependent, but a ballpark would be fine. I'm using the T89C51CC01 from Atmel if anyone knows the exact value for that micro. Could not find this either in the CC01 manual.

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  • Guys,
    Thanks very much for the replies. I have one more follow-up question I was hoping someone could answer: if I exceed the 128 bytes of data space but do not explicitly locate this extra data in idata space, will I also get a linker error, or will the compiler simply place this data in idata space?

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  • Guys,
    Thanks very much for the replies. I have one more follow-up question I was hoping someone could answer: if I exceed the 128 bytes of data space but do not explicitly locate this extra data in idata space, will I also get a linker error, or will the compiler simply place this data in idata space?

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