ADSP-BF531/ADSP-BF532/ADSP-BF533
The BMODE pins of the Reset Configuration Register, sampled
during power-on resets and software-initiated resets, imple-
ment the following modes:
• Execute from 16-bit external memory – Execution starts
from address 0x2000 0000 with 16-bit packing. The boot
ROM is bypassed in this mode. All configuration settings
are set for the slowest device possible (3-cycle hold time;
15-cycle R/W access times; 4-cycle setup).
• Boot from 8-bit or 16-bit external FLASH memory – The
FLASH boot routine located in boot ROM memory space is
set up using Asynchronous Memory Bank 0. All configura-
tion settings are set for the slowest device possible (3-cycle
hold time; 15-cycle R/W access times; 4-cycle setup).
• Boot from SPI serial EEPROM (8, 16, or 24-bit
addressable) – The SPI uses the PF2 output pin to select a
single SPI EEPROM device, submits successive read com-
mands at addresses 0x00, 0x0000, and 0x000000 until a
valid 8, 16, or 24-bit addressable EEPROM is detected, and
begins clocking data into the beginning of L1 instruction
memory.
For each of the boot modes, an 10-byte header is first read from
an external memory device. The header specifies the number of
bytes to be transferred and the memory destination address.
Multiple memory blocks may be loaded by any boot sequence.
Once all blocks are loaded, program execution commences from
the start of L1 instruction SRAM.
In addition, bit 4 of the Reset Configuration Register can be set
by application code to bypass the normal boot sequence during
a software reset. For this case, the processor jumps directly to
the beginning of L1 instruction memory.
• All registers, I/O, and memory are mapped into a unified
4G byte memory space, providing a simplified program-
ming model.
• Microcontroller features, such as arbitrary bit and bit-field
manipulation, insertion, and extraction; integer operations
on 8-, 16-, and 32-bit data-types; and separate user and
supervisor stack pointers.
• Code density enhancements, which include intermixing of
16- and 32-bit instructions (no mode switching, no code
segregation). Frequently used instructions are encoded in
16 bits.
DEVELOPMENT TOOLS
The ADSP-BF531/2/3 processor is supported with a complete
set of CROSSCORE®
†
software and hardware development
tools, including Analog Devices emulators and VisualDSP++®
‡
development environment. The same emulator hardware that
supports other Blackfin processors also fully emulates the
ADSP-BF531/2/3 processor.
The VisualDSP++ project management environment lets pro-
grammers develop and debug an application. This environment
includes an easy to use assembler (which is based on an alge-
braic syntax), an archiver (librarian/library builder), a linker, a
loader, a cycle-accurate instruction-level simulator, a C/C++
compiler, and a C/C++ runtime library that includes DSP and
mathematical functions. A key point for these tools is C/C++
code efficiency. The compiler has been developed for efficient
translation of C/C++ code to processor assembly. The processor
has architectural features that improve the efficiency of com-
piled C/C++ code.
The VisualDSP++ debugger has a number of important fea-
tures. Data visualization is enhanced by a plotting package that
offers a significant level of flexibility. This graphical representa-
tion of user data enables the programmer to quickly determine
the performance of an algorithm. As algorithms grow in com-
plexity, this capability can have increasing significance on the
designer’s development schedule, increasing productivity. Sta-
tistical profiling enables the programmer to nonintrusively poll
the processor as it is running the program. This feature, unique
to VisualDSP++, enables the software developer to passively
gather important code execution metrics without interrupting
the real-time characteristics of the program. Essentially, the
developer can identify bottlenecks in software quickly and effi-
ciently. By using the profiler, the programmer can focus on
those areas in the program that impact performance and take
corrective action.
Debugging both C/C++ and assembly programs with the
VisualDSP++ debugger, programmers can:
• View mixed C/C++ and assembly code (interleaved source
and object information).
• Insert breakpoints.
INSTRUCTION SET DESCRIPTION
The Blackfin processor family assembly language instruction set
employs an algebraic syntax designed for ease of coding and
readability. The instructions have been specifically tuned to pro-
vide a flexible, densely encoded instruction set that compiles to
a very small final memory size. The instruction set also provides
fully featured multifunction instructions that allow the pro-
grammer to use many of the processor core resources in a single
instruction. Coupled with many features more often seen on
microcontrollers, this instruction set is very efficient when com-
piling C and C++ source code. In addition, the architecture
supports both user (algorithm/application code) and supervisor
(O/S kernel, device drivers, debuggers, ISRs) modes of opera-
tion, allowing multiple levels of access to core processor
resources.
The assembly language, which takes advantage of the proces-
sor’s unique architecture, offers the following advantages:
• Seamlessly integrated DSP/CPU features are optimized for
both 8-bit and 16-bit operations.
• A multi-issue load/store modified-Harvard architecture,
which supports two 16-bit MAC or four 8-bit ALU + two
load/store + two pointer updates per cycle.
†
‡
CROSSCORE is a registered trademark of Analog Devices, Inc.
VisualDSP++ is a registered trademark of Analog Devices, Inc.
Rev. 0 |
Page 14 of 56 | March 2004
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