Global Data Memory
4-13
Memory and I/O Spaces
toggled between local memory and global memory. For example, in the system
of Figure 4–6, when GREG = XXXXXXXX00000000
2
(no global memory), the
local data RAM is fully accessible; when GREG = XXXXXXXX10000000
2
(all
global memory), the local data RAM is not accessible.
Figure 4–6. Using 8000h–FFFFh for Local and Global External Memory
Local data RAM
8000h–FFFFh
A15 – A0
A15 – A0
’C2xx
D15–D0
D15– D0
OE
CE
RD
BR
16
16
A15 – A0
D15– D0
CE
WE
WE
DS
16
16
OE
WE
Global data RAM
8000h–FFFFh