TMS320F2810, TMS320F2812
DIGITAL SIGNAL PROCESSORS
SPRS174B – APRIL 2001 – REVISED SEPTEMBER 2001
14
POST OFFICE BOX 1443 • HOUSTON, TEXAS 77251–1443
memory map (continued)
The “Low 64K” of the memory address range maps into the data space of the 240x. The “High 64K” of the
memory address range maps into the program space of the 24x/240x. 24x/240x-compatible code will only
execute from the “High 64K” memory area. Hence, the top 32K of Flash and H0 SARAM block can be used to
run 24x/240x-compatible code (if MP/MC
mode is low) or, on F2812, code can be executed from XINTF Zone 7
(if MP/MC
mode is high).
The XINTF consists of five independent zones. Three zones have their own chip selects and two zones share
a single chip select. Each zone can be programmed with its own timing (wait states) and to either sample or
ignore external ready signal. This makes interfacing to external peripherals easy and glueless.
Note: The chip selects of XINTF Zone 6 and Zone 7 are merged together into a single chip select (ZCS6AND7
).
Refer to the ”External Interface – XINTF (F2812 only)” section of this data sheet for details.
Peripheral Frame 1, Peripheral Frame 2, and XINTF Zone 1 are grouped together so as to enable these blocks
to be “write/read peripheral block protected”. The “protected” mode ensures that all accesses to these blocks
happen as written. Because of the C28x pipeline, a write immediately followed by a read, to different memory
locations, will appear in reverse order on the memory bus of the CPU. This can cause problems in certain
peripheral applications where the user expected the write to occur first (as written). The C28x CPU supports
a block protection mode where a region of memory can be protected so as to make sure that operations occur
as written (the penalty is extra cycles are added to align the operations). This mode is programmable and by
default, it will protect the selected zones.
On the F2812, at reset, XINTF Zone 7 is enabled if the XMP/MC
signal is pulled high. This signal selects
microprocessor or microcomputer mode of operation. In microprocessor mode, Zone 7 is mapped to high
memory such that the vector table is fetched externally. The Boot ROM is disabled in this mode. In
microcomputer mode, Zone 7 is disabled such that the vectors are fetched from Boot ROM. This allows the user
to either boot from on-chip memory or from off-chip memory. The state of the XMP/MC
signal on reset is stored
in an MP/MC
mode bit in the XINTCNF2 register. The user can change this mode in software and hence control
the mapping of Boot ROM and XINTF Zone 7. No other memory blocks are affected by XMP/MC
.
I/O space is not supported on the F2812 XINTF.
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