Booting Process
19-28
ADSP-BF537 Blackfin Processor Hardware Reference
chosen by the
BMODE
pins. In the three master modes that boot from flash,
SPI or TWI memory, this is not possible. Therefore, the on-chip boot
ROM provides special support for these three boot modes.
When a different application (
.DXE
) needs to be booted into a running
Blackfin, it should be booted into the processor’s internal memory. Pro-
grams do not require simulating the built-in boot kernel—instead, the
original kernel can be reused for this purpose. The boot ROM provides
the proper entry addresses for the three master boot modes. All three func-
tions expect register
R7
to hold the start address where the boot stream to
be booted resides. For flash boot the following sequence may boot in a
stream that is stored in asynchronous memory bank 1.
#include <defBF537.h> /* provides function entry addresses */
P0.H = HI(_BOOTROM_Boot_DXE_Flash) ;
P0.L = LO(_BOOTROM_Boot_DXE_Flash) ;
R7.H = HI(0x20100000) ; /* start of async bank 1 */
R7.L = LO(0x20100000) ;
JUMP (P0) ; /* jump to Boot ROM */
This example assumes that the
AMS1
strobe has already been activated. The
function determines whether an 8-bit or a 16-bit memory device is con-
nected. Note that the boot stream may also reside in SRAM or SDRAM
memory.
The SPI master boot from flash version takes two more parameters:
R6
,
which holds the GPIO on port F that the SPI memory’s
CS
input connects
to, and
R5
which holds the value that is written to the
SPI_BAUD
register
internally. Since the routine writes this value directly into the
PORTFIO_DIR
register, other GPIOs on port F might be impacted. The fol-
lowing example loads a boot stream from address 0 of an SPI memory
connected to the
PF4
pin:
#include <defBF537.h> /* provides function entry addresses */
P0.H = HI(_BOOTROM_Boot_DXE_SPI) ;
Summary of Contents for Blackfin ADSP-BF537
Page 42: ...Contents xlii ADSP BF537 Blackfin Processor Hardware Reference ...
Page 90: ...Development Tools 1 32 ADSP BF537 Blackfin Processor Hardware Reference ...
Page 138: ...Programming Examples 4 26 ADSP BF537 Blackfin Processor Hardware Reference ...
Page 340: ...SDC Programming Examples 6 84 ADSP BF537 Blackfin Processor Hardware Reference ...
Page 606: ...Programming Examples 9 94 ADSP BF537 Blackfin Processor Hardware Reference ...
Page 660: ...Programming Examples 10 54 ADSP BF537 Blackfin Processor Hardware Reference ...
Page 720: ...Electrical Specifications 11 60 ADSP BF537 Blackfin Processor Hardware Reference ...
Page 840: ...Programming Examples 13 42 ADSP BF537 Blackfin Processor Hardware Reference ...
Page 876: ...Programming Examples 14 36 ADSP BF537 Blackfin Processor Hardware Reference ...
Page 938: ...Programming Examples 15 62 ADSP BF537 Blackfin Processor Hardware Reference ...
Page 958: ...Programming Examples 17 12 ADSP BF537 Blackfin Processor Hardware Reference ...
Page 986: ...Programming Examples 18 28 ADSP BF537 Blackfin Processor Hardware Reference ...
Page 1162: ...G 26 ADSP BF537 Blackfin Processor Hardware Reference ...
Page 1218: ...Index I 56 ADSP BF537 Blackfin Processor Hardware Reference ...