Analog Devices VISUALDSP++ 3.5, Руководство пользователя

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Vi+ Loader Manual 3-13
for 16-Bit Processors
ADSP-219x DSP Loader/Splitter
signal (
/MS0
). Splitter capabilities of the ADSP-219x loader utility support
the generation of the required EPROM image files. Refer to the loader’s
-romsplitter
switch (see on page 3-23 ) for more information.
Non-bootable memory segments are declared by the
TYPE(ROM)
command
in the Linker Description File (
.LDF
). The
WIDTH()
command specifies the
physical EPROM width (which equals to the EMI port setting). Every
.LDF
file that belongs to a no-boot project should define a proper memory
segment; as in the following example,
MEMORY {
. . .
seg_ext_code {
TYPE(PM ROM) START(0x010000) END(0x017FFF) WIDTH(16) }
. . .
}
The
START()
,
END()
, and
LENGTH()
commands expect logical addresses.
Since the example segment stores 24-bit-wide instructions, the
TYPE(PM)
command defines the logical width of the segment to be 24-bits. The
example assumes no-boot mode (
000
) and runs from external memory
starting at address
0x010000
. This is why the
WIDTH(16)
command sets the
physical width to 16 bits. Due to ADSP-219x EMI packing rules, the first
instruction is stored in the physical 16-bit EPROM location
0x020000
.
The 16-bit EPROM address locations between
0x010000
and
0x01FFFF
can be used by an additional read-only data segment as shown below.
MEMORY {
. . .
seg_ext_code {
TYPE(PM ROM) START(0x010000) END(0x017FFF) WIDTH(16) }
seg_ext_data {
TYPE(DM ROM) START(0x010000) END(0x01FFFF) WIDTH(16) }
. . .
}