I try to use sdcc with the Philips 89C51RD+ which contains
768 bytes of external RAM inside the chip. It seems to me
that it cannot access the external memory. Any suggestion
will be appreciate.
From: ben knight <bkk@oz...> - 2001-02-10 12:32:23
Make sure that you set EXTRAM to 1 before accessing the memory,
otherwise the MCU will attempt to access external memory - ie: via the
external busses. Setting EXTRAM to 1 tells the MCU that all references
to the lower 768 bytes of external memory are in fact referring to the
EXTRAM is bit #1 of SFR AUXR. AUXR is at address 0x8e.
i have a cunning plan....