Intel 8253 - Page 333

XA User Guide 2-3 3/24/97
Figure 2.2 XA data memory segments
Figure 2.3 Simplified XA data memory diagram
Segment 0
Segment 255
(Segment n)
Segment 1
64K bytes
0
FFFFh (64K)
The on-chip/off-chip data
memory boundary varies
for different XA derivatives
On-chip
data memory
Off-chip
data memory
The direct
addressing mode
limit is at 1K (3FFh)
The entire memory is
addressable in the
indirect and indirect
with offset modes