Texas Instruments TMS320C80, Руководство пользователя

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Memory Differences
1-6 TMS320C80 to TMS320C82 Software Compatibility User’s Guide
1.5 Memory Differences
The ’C80 has 50 KB of on-chip RAM, and the ’C82 has 44 KB of
on-chip RAM. On-chip RAM is used as data RAM, as parameter
RAM, and as instruction and data caches.
The ’C80’s RAM is partitioned into 25 individual 2-KB modules.
In contrast, the ’C82’s RAM is partitioned into 11 individual 4-KB
modules. Modules can be accessed in parallel over the crossbar
during the same clock cycle without contention. However, since
RAM organization is not identical in the ’C80 and ’C82, conten-
tion may occur in one device without occurring in the other if your
program does not compensate for this difference.
For your reference, the memory maps of the ’C80 and ’C82 are
described in Appendix A.
1.5.1 Data RAMs
Data RAMs are standard read/write memory with no caching or
special features. They are the main areas in which the PPs store
the data they are processing. Any transfer of data to or from data
RAMs is done explicitly by the processors, either by a direct read
from or write to memory, or by a request to the TC to transfer the
data through packet transfers.
As Figure 1–1 illustrates, all data RAM locations corresponding
to PP0 and PP1 on the ’C80 are populated with data RAM on the
’C82. Thus, the ’C82’s data-RAM map for PP0 and PP1 is a su-
perset of the ’C80’s. The last half of each of the 4-KB memory
spaces occupied by the ’C82’s PP0 data RAM 1 and PP1 data
RAM 1 is unpopulated on the ’C80. The memory locations occu-
pied by the ’C80’s data RAMs for PP2 and PP3 are unpopulated
on the ’C82.