AT90USB1286-16MU ATMEL [ATMEL Corporation], AT90USB1286-16MU Datasheet - Page 36

• Manufacturer Part Number: AT90USB1286-16MU
• Description: Microcontroller with 64/128K Bytes of ISP Flash and USB Controller
• Manufacturer: ATMEL [ATMEL Corporation]

5.5.9
36
AT90USB64/128
Using all 64KB Locations of External Memory
Figure 5-10. Address Map with 32 KB External Memory
Since the External Memory is mapped after the Internal Memory as shown in
56KB of External Memory is available by default (address space 0x0000 to 0x20FF is reserved
for internal memory). However, it is possible to take advantage of the entire External Memory by
masking the higher address bits to zero. This can be done by using the XMMn bits and control
by software the most significant bits of the address. By setting Port C to output 0x00, and releas-
ing the most significant bits for normal Port Pin operation, the Memory Interface will address
0x0000 - 0x2FFF. See the following code examples.
Care must be exercised using this option as most of the memory is masked away.
ISRAM end + 0x8000
XMem start + 0x8000
0 x 0000
0 x 20FF
0 x 2100
0 x 7FFF
0 x 8000
0 x FFFF
AVR M emory M ap
I nternal M emory
E xternal
(U nused )
M emory
M emory C onfiguration A
E xternal 32K S RAM
0 x 0000
ISRAM end
XMem start
0 x 7FFF
Figure
7593A–AVR–02/06
5-4, only