Basic Booting Process
24-16
ADSP-BF50x Blackfin Processor Hardware Reference
The
BFLAG_FIRST
flag must not be combined with the
BFLAG_FILL
flag.
The
BFLAG_FIRST
flag may be combined with the
BFLAG_IGNORE
flag to
deposit special user data at the top of the boot stream. Note the special
importance of the elfloader
–readall
switch.
Header Checksum Field
The header checksum (
HDRCHK
) field holds a simple XOR checksum of the
other 31 bytes in the boot block header. The boot kernel jumps to the
error routine if the result of an XOR operation across all 32 header bytes
(including the
HDRCHK
value) differs from zero. The default error routine is
12
BFLAG_IGNORE
Indicates a block that is not booted into memory. It instructs the
boot kernel to skip the number of bytes of the boot stream as spec-
ified by
BYTE COUNT
. In master boot modes, the boot kernel sim-
ply modifies its source address pointer. In this case the
BYTE COUNT
value can be seen as a 32-bit two’s-complement offset
value to be added to the source address pointer. In slave boot
modes, the boot kernel actively loads and changes the payload of
the block. In slave modes the byte count must be a positive value.
13
BFLAG_INDIRECT
Boots to an intermediate storage place, allowing for calling an
optional callback function, before booting to the destination. This
flag is used when the boot source does not have DMA support and
either the destination cannot be accessed by the core (L1 instruc-
tion SRAM) or cannot be efficiently accessed by the core. This flag
is also used when
CALLBACK
requires access to data to calculate a
checksum, or when performing tasks such as decryption or decom-
pression.
14
BFLAG_FIRST
This flag, which is only set on the first block of a DXE, tells the
boot kernel about the special nature of the
TARGET ADDRESS
and
the
ARGUMENT
fields. The
TARGET ADDRESS
field holds the start
address of the application. The
ARGUMENT
field holds the offset to
the next DXE.
15
BFLAG_FINAL
This flag causes the boot kernel to pass control over to the applica-
tion after the final block is processed. This flag is usually set on the
last block of a DXE unless multiple DXEs are merged.
Table 24-4. Block Flags (Cont’d)
Bit Name
Description
Содержание EZ-KIT Lite ADSP-BF506F
Страница 50: ...Contents l ADSP BF50x Blackfin Processor Hardware Reference ...
Страница 92: ...Development Tools 1 30 ADSP BF50x Blackfin Processor Hardware Reference ...
Страница 110: ...Interface Overview 3 12 ADSP BF50x Blackfin Processor Hardware Reference ...
Страница 132: ...Unique Information for the ADSP BF50x Processor 4 22 ADSP BF50x Blackfin Processor Hardware Reference ...
Страница 236: ...Internal Flash Memory Control Registers 6 92 ADSP BF50x Blackfin Processor Hardware Reference ...
Страница 342: ...Unique Information for the ADSP BF50x Processor 7 106 ADSP BF50x Blackfin Processor Hardware Reference ...
Страница 484: ...Unique Information for the ADSP BF50x Processor 10 60 ADSP BF50x Blackfin Processor Hardware Reference ...
Страница 493: ...ADSP BF50x Blackfin Processor Hardware Reference 11 9 Core Timer Unique Information for the ADSP BF50x Processor None ...
Страница 494: ...Unique Information for the ADSP BF50x Processor 11 10 ADSP BF50x Blackfin Processor Hardware Reference ...
Страница 506: ...Unique Information for the ADSP BF50x Processor 12 12 ADSP BF50x Blackfin Processor Hardware Reference ...
Страница 544: ...Unique Information for the ADSP BF50x Processor 13 38 ADSP BF50x Blackfin Processor Hardware Reference ...
Страница 650: ...Programming Examples 15 56 ADSP BF50x Blackfin Processor Hardware Reference ...
Страница 712: ...Unique Information for the ADSP BF50x Processor 16 62 ADSP BF50x Blackfin Processor Hardware Reference ...
Страница 804: ...Programming Examples 17 92 ADSP BF50x Blackfin Processor Hardware Reference ...
Страница 972: ...Unique Information for the ADSP BF50x Processor 20 38 ADSP BF50x Blackfin Processor Hardware Reference ...
Страница 1194: ...Programming Examples 24 90 ADSP BF50x Blackfin Processor Hardware Reference ...
Страница 1256: ...ACM Registers A 50 ADSP BF50x Blackfin Processor Hardware Reference ...
Страница 1264: ...Boundary Scan Architecture B 8 ADSP BF50x Blackfin Processor Hardware Reference ...