about defining charactre arrays

hey
i a working at insignia technologies and i have a problem with defining character arrays
actually i am programming a 89C51RD2 chip using flash magic and i have a problem with programs that have array size espeially two dimensional arrays of size of 150 and more as well as structures
"Although the program compiles" but the LCD which initially displays any message doesnt seem to respond to the new program and just goes blank
could anyone please help me with this definition of two dimensional arrays of size 100 and more as well as structures.THis is urgent please
Could anyone tell me the reason why this is happening and what could be done to avoid this

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  • Hi maheshwari, you must make sure that big arrays and structures are declared in xdata memory area. Additionally the 89c51rd2 has 1024 bytes internal RAM accessed via MOVX instructions, make sure your arrays and structures doesnt go beyond that limit.

    One extra tip is checking the memory enabling bits, the 89c51rd2 normally only has 256 bytes of XRAM enabled by default, to modify this behaviour you must set bits XRS1 and XRS0 in register AUXR(8Eh).

    Check the device datasheet for more details.

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  • Hi maheshwari, you must make sure that big arrays and structures are declared in xdata memory area. Additionally the 89c51rd2 has 1024 bytes internal RAM accessed via MOVX instructions, make sure your arrays and structures doesnt go beyond that limit.

    One extra tip is checking the memory enabling bits, the 89c51rd2 normally only has 256 bytes of XRAM enabled by default, to modify this behaviour you must set bits XRS1 and XRS0 in register AUXR(8Eh).

    Check the device datasheet for more details.

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