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 = XXXXXXXX000000002 (no global memory), the

local data RAM is fully accessible; when GREG = XXXXXXXX100000002 (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–A0A15–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