SPRS174S – APRIL 2001 – REVISED MARCH 2011
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user can also single step through non-time critical code while enabling time-critical interrupts to be
serviced without interference. The F281x and C281x implement the real-time mode in hardware within the
CPU. This is a unique feature to the F281x and C281x, no software monitor is required. Additionally,
special analysis hardware is provided that allows the user to set hardware breakpoint or data/address
watch-points and generate various user selectable break events when a match occurs.
3.2.5
External Interface (XINTF) (2812 Only)
This asynchronous interface consists of 19 address lines, 16 data lines, and three chip-select lines. The
chip-select lines are mapped to five external zones, Zones 0, 1, 2, 6, and 7. Zones 0 and 1 share a single
chip-select; Zones 6 and 7 also share a single chip-select. Each of the five zones can be programmed
with a different number of wait states, strobe signal setup and hold timing and each zone can be
programmed for extending wait states externally or not. The programmable wait-state, chip-select and
programmable strobe timing enables glueless interface to external memories and peripherals.
3.2.6
Flash (F281x Only)
The F2812 and F2811 contain 128K x 16 of embedded flash memory, segregated into four 8K x 16
sectors, and six 16K x 16 sectors. The F2810 has 64K x 16 of embedded flash, segregated into two 8K x
16 sectors, and three 16K x 16 sectors. All three devices also contain a single 1K x 16 of OTP memory at
address range 0x3D 7800–0x3D 7BFF. The user can individually erase, program, and validate a flash
sector while leaving other sectors untouched. However, it is not possible to use one sector of the flash or
the OTP to execute flash algorithms that erase/program other sectors. Special memory pipelining is
provided to enable the flash module to achieve higher performance. The flash/OTP is mapped to both
program and data space; therefore, it can be used to execute code or store data information.
NOTE
The F2810/F2811/F2812 Flash and OTP wait states can be configured by the application.
This allows applications running at slower frequencies to configure the flash to use fewer
wait states.
Flash effective performance can be improved by enabling the flash pipeline mode in the
Flash options register. With this mode enabled, effective performance of linear code
execution will be much faster than the raw performance indicated by the wait state
configuration alone. The exact performance gain when using the Flash pipeline mode is
application-dependent.
For more information on the Flash options, Flash wait-state, and OTP wait-state registers,
see the
TMS320x281x DSP System Control and Interrupts Reference Guide
(literature
number
3.2.7
ROM (C281x Only)
The C2812 and C2811 contain 128K x 16 of ROM. The C2810 has 64K x 16 of ROM. In addition to this,
there is a 1K x 16 ROM block that replaces the OTP memory available in flash devices. For information on
how to submit ROM codes to TI, see the
TMS320C28x CPU and Instruction Set Reference Guide
(literature number
3.2.8
M0, M1 SARAMs
All C28x devices contain these two blocks of single access memory, each 1K x 16 in size. The stack
pointer points to the beginning of block M1 on reset. The M0 block overlaps the 240x device B0, B1, B2
RAM blocks and hence the mapping of data variables on the 240x devices can remain at the same
physical address on C28x devices. The M0 and M1 blocks, like all other memory blocks on C28x devices,
are mapped to both program and data space. Hence, the user can use M0 and M1 to execute code or for
data variables. The partitioning is performed within the linker. The C28x device presents a unified memory
map to the programmer. This makes for easier programming in high-level languages.
34
Functional Overview
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