Texas Instruments TMS320C54x, Руководство пользователя, Страница: 337 / 469

Controlling the ROM Device Address
10-37 Hex Conversion Utility Description
10.10.4 Dealing With Address Holes
When memory width is different from data width, the automatic multiplication
of the load address by the correction factor might create holes at the beginning
of a section or between sections.
For example, assume you want to load a COFF section (.sec1) at address
0x0100 of an 8-bit EPROM. If you specify the load address in the linker com-
mand file at location 0x0100, the hex conversion utility will multiply the address
by 2 (data width divided by memory width = 16/8 = 2), giving the output file a
starting address of 0x0200. Unless you control the starting address of the
EPROM with your EPROM programmer, you could create holes within the
EPROM. The programmer will burn the data starting at location 0x0200
instead of 0x0100. To solve this, you can:
-
Use the paddr parameter of the SECTIONS directive. This forces a sec-
tion to start at the specified value. Figure 10–9 shows a command file that
can be used to avoid the hole at the beginning of .sec1.
Figure 10–9. Hex Command File for Avoiding a Hole at the Beginning of a Section
–i
a.out
–map a.map
ROMS
{
ROM : org = 0x0100, length = 0x200, romwidth = 8,
memwidth = 8
}
SECTIONS
{
sec1: paddr = 0x100
}
Note: If your file contains multiple sections, and, if one section uses a paddr parameter,
then all sections must use the paddr parameter.
-
Use the –bootorg option or use the ROMS origin parameter (for boot
loading only). As described on page 10-35, when you are boot loading,
the EPROM address of the entire boot-loader table can be controlled by
the –bootorg option or by the ROMS directive origin.
-
For another example, see Section C.4, Example 3: Generating a Boot
Table for Non-LP Core Devices, on page C-10.