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VisualDSP++ 4.5 Loader and Utilities Manual - Analog Devices

VisualDSP++ 4.5 Loader and Utilities Manual - Analog Devices

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ADSP-21161 Processor Booting<br />

3. Release the bus<br />

4. Execute the loaded instructions<br />

Boot From a Single EPROM<br />

The loader utility can produce boot-loadable files that permit SHARC<br />

processors in a multiprocessor system to boot from a single EPROM. The<br />

BMS signals from each processor may be wire ORed together to drive the<br />

EPROM’s chip select pin. Each processor can boot in turn, according to<br />

its priority. When the last processor has finished booting, it must inform<br />

the other processors (which may be in the idle state) that program execution<br />

can begin (if all processors are to begin executing instructions<br />

simultaneously).<br />

When multiple processors boot from a single EPROM, the processors can<br />

boot identical code or different code from the EPROM. If the processors<br />

load differing code, use a jump table in the loader file (based on processor<br />

ID) to select the code for each processor.<br />

Sequential EPROM Boot<br />

Set the EBOOT pin of the processor with ID# of 1 high for EPROM booting.<br />

The other processors should be configured for host boot (EBOOT=0,<br />

LBOOT=0, <strong>and</strong> BMS=1), leaving them in the idle state at startup <strong>and</strong> allowing<br />

the processor with ID=1 to become bus master <strong>and</strong> boot itself. Connect the<br />

BMS pin of processor #1 only to the EPROM’s chip select pin. When<br />

processor #1 has finished booting, it can boot the remaining processors by<br />

writing to their external port DMA buffer 0 (EPB0) via the multiprocessor<br />

memory space.<br />

4-22 <strong>VisualDSP++</strong> <strong>4.5</strong> <strong>Loader</strong> <strong>and</strong> <strong>Utilities</strong> <strong>Manual</strong>

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