I am working with a DS89c450 and uVision3.
My simple C code project consists of just the ds89c450, no other devices. I have the memory Model set to small (variables in DATA) Code ROM size set to 64K, and the option boxes for "Use on chip ROM (0x0-0xFFFF)" and "Use on chip XRAM (0x0-0x3FF) bot checked.
I'm compiling what I think is relatively small program that doesn't use a tremendous amount of RAM, but I am still getting the Address Space Overflow error L107 - referring to the DATA space.
It is not clear to me whether or not I am really using the 1K internal RAM. I can remove a single 1 byte variable and compile fine. I then look in the M51 listing file and the DATA amounts only total about 120 bytes.
How I be sure the compiler is really using the internal 1K RAM ... and have it place whatever variables can't fit elsewhere there ?
Thanks
My 8051 knowledge is awfully rusty, but as I recall only the first 256 bytes of memory are directly addressable, and a large portion of that is shadowed by the SFR, ie where a lot of the "zero page" stuff is actually registers. The rest of the larger memory arena is then accessed indirectly via XDATA, paging, or whatever, including space that might be masked by internal registers from the direct view.
The documentation for your specific part may spread some light on the implementation details.