Indirect Booting - Analog Devices ADSP-BF506F Hardware Reference Manual

Although the
BFLAG_INIT
not want to combine the
The initialization code can interrogate the
conditional instructions.

Indirect Booting

The processor's boot kernel provides a control mechanism to let blocks
either boot directly to their final destination or load to an intermediate
storage place, then copy the data to the final destination in a second step.
This feature is motivated by the following requirements:
• Some boot modes do not use DMA. They load data by core
instruction. The core cannot access some memories directly (for
example L1 instruction SRAM), or is less efficient than the DMA
in accessing some memories.
• In some advanced booting scenarios, the core needs to access the
boot data during the booting process, for example in processing
decompression, decryption and checksum algorithms at boot time.
The indirect booting option helps speed-up and simplify such sce-
narios. Software accesses off-chip memory less efficiently and
cannot access data directly if it resides in L1 instruction SRAM.
Indirect booting is not a global setting. Every boot block can control its
own processing by the
In general a boot block may not fit into the temporary storage memory so
the boot kernel processes the block in multiple steps. The larger the tem-
porary buffer, the faster the boot process. By default the L1 data memory
region between 0xFF80 7F00 and 0xFF80 7FEF is used for intermediate
storage. Initialization code can alter this region by modifying the
and
pTempBuffer
ture. The default region is at the upper end of a physical memory block.
ADSP-BF50x Blackfin Processor Hardware Reference
flag is suppressed in quick boot, the user may
BFLAG_INIT
BFLAG_INDIRECT
variables in the
dTempByteCount
System Reset and Booting
flag with the
BFLAG_QUICKBOOT
BFLAG_WAKEUP
flag in the block header.
ADI_BOOT_DATA
flag.
flag and execute
struc-
24-29