
Basic Booting Process
16-20
ADSP-BF59x Blackfin Processor Hardware Reference
boot kernel provides options to execute an
RTS
instruction or a
RAISE 1
instruction instead. The default behavior can be changed by an initcode
routine. The
EVT1
register is updated by the boot kernel when processing
the
BFLAG_FIRST
block. See
“Servicing Reset Interrupts” on page 16-6
to
learn how the application can take control.
Before the boot kernel passes program control to the application it does
some housekeeping. Most of the registers that were used are changed back
to their default state but some register values may differ for individual
boot modes. DMA configuration registers and primary register control
registers (
UARTx_LCR
,
SPIx_CTL
, etc.) are restored, while others are pur-
posely not restored. For example
SPIx_BAUD
,
UARTx_DLH
and
UARTx_DLL
remain unchanged so that settings obtained during the booting process are
not lost.
Single Block Boot Streams
The simplest boot stream consists of a single block header and one contig-
uous block of instructions. With appropriate flag instructions the boot
kernel loads the block to the target address and immediately terminates by
executing the loaded block.
Table 16-5
shows an example of a single block boot stream header that
could be loaded from any serial boot mode. It places a 256-byte block of
instructions at L1 instruction SRAM address 0xFFA0 0000. The flags
BFLAG_FIRST
and
BFLAG_FINAL
are both set at the same time. Advanced
flags, such as
BFLAG_IGNORE
,
BFLAG_INIT
,
BFLAG_CALLBACK
and
BFLAG_FILL
, do not make sense in this context and should not be used.
Table 16-5. Header for a Single Block Boot Stream
Field
Value
Comments
BLOCK CODE
0xAD33 C001 0xAD00 0000 | XORSUM | BFLAG_FINAL |
BFLAG_FIRST | (DMACODE & 0x1)
TARGET ADDRESS 0xFFA0 0000
Start address of block and application code
Summary of Contents for ADSP-BF59x Blackfin
Page 64: ...Development Tools 1 22 ADSP BF59x Blackfin Processor Hardware Reference...
Page 74: ...Processor Specific MMRs 2 10 ADSP BF59x Blackfin Processor Hardware Reference...
Page 244: ...Programming Examples 6 40 ADSP BF59x Blackfin Processor Hardware Reference...
Page 700: ...Programming Examples 16 78 ADSP BF59x Blackfin Processor Hardware Reference...
Page 738: ...Boundary Scan Architecture B 8 ADSP BF59x Blackfin Processor Hardware Reference...