TMS320F28335, TMS320F28334, TMS320F28332
TMS320F28235, TMS320F28234, TMS320F28232
SPRS439I–JUNE 2007–REVISED MARCH 2011
3.2 Brief Descriptions
3.2.1 C28x CPU
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The F2833x (C28x+FPU)/F2823x (C28x) family is a member of the TMS320C2000™ digital signal
controller (DSC) platform. The C28x+FPU based controllers have the same 32-bit fixed-point architecture
as TI's existing C28x DSCs, but also include a single-precision (32-bit) IEEE 754 floating-point unit (FPU).
It is a very efficient C/C++ engine, enabling users to develop their system control software in a high-level
language. It also enables math algorithms to be developed using C/C++. The device is as efficient at DSP
math tasks as it is at system control tasks that typically are handled by microcontroller devices. This
efficiency removes the need for a second processor in many systems. The 32 x 32-bit MAC 64-bit
processing capabilities enable the controller to handle higher numerical resolution problems efficiently.
Add to this the fast interrupt response with automatic context save of critical registers, resulting in a device
that is capable of servicing many asynchronous events with minimal latency. The device has an
8-level-deep protected pipeline with pipelined memory accesses. This pipelining enables it to execute at
high speeds without resorting to expensive high-speed memories. Special branch-look-ahead hardware
minimizes the latency for conditional discontinuities. Special store conditional operations further improve
performance.
The F2823x family is also a member of the TMS320C2000™ digital signal controller (DSC) platform but it
does not include a floating-point unit (FPU).
3.2.2 Memory Bus (Harvard Bus Architecture)
As with many DSC type devices, multiple busses are used to move data between the memories and
peripherals and the CPU. The C28x memory bus architecture contains a program read bus, data read bus
and data write bus. The program read bus consists of 22 address lines and 32 data lines. The data read
and write busses consist of 32 address lines and 32 data lines each. The 32-bit-wide data busses enable
single cycle 32-bit operations. The multiple bus architecture, commonly termed Harvard Bus, enables the
C28x to fetch an instruction, read a data value and write a data value in a single cycle. All peripherals and
memories attached to the memory bus will prioritize memory accesses. Generally, the priority of memory
bus accesses can be summarized as follows:
Highest:
Data Writes
(Simultaneous data and program writes cannot occur on the
memory bus.)
Program Writes (Simultaneous data and program writes cannot occur on the
memory bus.)
Data Reads
Program
Reads
(Simultaneous program reads and fetches cannot occur on the
memory bus.)
Lowest:
Fetches
(Simultaneous program reads and fetches cannot occur on the
memory bus.)
3.2.3 Peripheral Bus
To enable migration of peripherals between various Texas Instruments (TI) DSC family of devices, the
2833x/2823x devices adopt a peripheral bus standard for peripheral interconnect. The peripheral bus
bridge multiplexes the various busses that make up the processor Memory Bus into a single bus
consisting of 16 address lines and 16 or 32 data lines and associated control signals. Three versions of
the peripheral bus are supported. One version supports only 16-bit accesses (called peripheral frame 2).
Another version supports both 16- and 32-bit accesses (called peripheral frame 1). The third version
supports DMA access and both 16- and 32-bit accesses (called peripheral frame 3).
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Functional Overview
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