Analog Devices VisualDSP++ 3.5 Manual page 100

ADSP-219x DSP Booting
The data segment
which sets the logical width to 16 bits. Since the
sets the physical width to 16 bit, no data packing and no address multiply
is required. Logical addresses are equal to physical EPROM addresses in
this special case. The 16-bit EPROM image generated by the loader is
described in Table
Table 3-2. EPROM Image Description
Address range
0x000000–0x00FFFF
0x010000–0x01FFFF
0x020000–0x02FFFF
!
The DSP cannot access off-chip addresses lower than
Typically this address space is accessed by taking advantage of
address aliasing. The memory strobe (
from
0x010000
than 4M words and the EPROM is the only device connected to
, the first 64K words can be accessed through addresses
/MS0
0x200000
If a project consists only of two segments (
), a 128K x 16-bit EPROM device would be sufficient to
seg_ext_code
store all the required data and instructions. If the loader utility is invoked
with the
-maskaddr 17
greater than or equal to
addresses with
seg_ext_code
This way, a 128K x 16-bit EPROM can be burned properly. At runtime,
seg_ext_code
lines through
A17
3-14
seg_ext_data
3-2:
Purpose
Not used
seg_ext_data
seg_ext_code
to
0x400000
to .
0x20FFFF
switch (on page
are masked out. The loader ANDs all physical
A17
. The resulting EPROM image maps segment
0x01FFFF
into the unused space below
aliases back to the addresses above
are not connected.
A21
is defined by the
TYPE(DM)
WIDTH(16)
) covers an address range
/MS0
. For example, if the EPROM size is less
seg_ext_data
3-22), all physical address bits
0x010000
0x020000
VisualDSP++ Loader Manual
command,
command also
.
0x010000
and
(see Table 3-3).
when address
for 16-Bit Processors