Datasheet
TMS320F28027, TMS320F28026, TMS320F28023, TMS320F28022
TMS320F28021, TMS320F28020, TMS320F280200
SPRS523J –NOVEMBER 2008–REVISED OCTOBER 2013
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3.2.4 Real-Time JTAG and Analysis
The devices implement the standard IEEE 1149.1 JTAG
(1)
interface for in-circuit based debug.
Additionally, the devices support real-time mode of operation allowing modification of the contents of
memory, peripheral, and register locations while the processor is running and executing code and
servicing interrupts. The user can also single step through non-time-critical code while enabling time-
critical interrupts to be serviced without interference. The device implements the real-time mode in
hardware within the CPU. This is a feature unique to the 28x family of devices, requiring no software
monitor. Additionally, special analysis hardware is provided that allows setting of hardware breakpoint or
data/address watch-points and generating various user-selectable break events when a match occurs.
These devices do not support boundary scan; however, IDCODE and BYPASS features are available if
the following considerations are taken into account. The IDCODE does not come by default. The user
needs to go through a sequence of SHIFT IR and SHIFT DR state of JTAG to get the IDCODE. For
BYPASS instruction, the first shifted DR value would be 1.
3.2.5 Flash
The F280200 device contains 8K x 16 of embedded flash memory, segregated into two 4K x 16 sectors.
The F28021/23/27 devices contain 32K x 16 of embedded flash memory, segregated into four 8K x 16
sectors. The F28020/22/26 devices contain 16K x 16 of embedded flash memory, segregated into four
4K x 16 sectors. All 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. Addresses 0x3F 7FF0 – 0x3F 7FF5
are reserved for data variables and should not contain program code.
NOTE
The 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 TMS320x2802x/TMS320F2802xx Piccolo System Control and Interrupts Reference
Guide (literature number SPRUFN3).
3.2.6 M0, M1 SARAMs
All 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 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.
3.2.7 L0 SARAM
The device contains up to 4K x 16 of single-access RAM. Refer to the device-specific memory map figures
in Section 3.1 to ascertain the exact size for a given device. This block is mapped to both program and
data space.
(1) IEEE Standard 1149.1-1990 Standard Test Access Port and Boundary Scan Architecture
24 Functional Overview Copyright © 2008–2013, Texas Instruments Incorporated
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