ADSP-BF537 Blackfin Processor Hardware Reference
19-29
System Reset and Booting
P0.L = LO(_BOOTROM_Boot_DXE_SPI) ;
R7 = 0 (Z) ; /* SPI address is zero */
R6 = PF4 (z) ; /* SPI's /CS connects to PF4 pin */
R5 = 0x0085(Z) ; /* SPI clock divider */
JUMP (P0) ; /* jump to Boot ROM */
Note the following additional points on master booting from flash.
• For standard booting after reset, connect the SPI memory’s chip
select to the
PF10
pin. The example above assumes a second SPI
device is connected to the
PF4
pin.
• The optimal
SPI_BAUD
value written to
R5
depends on the
SCLK
clock rate and the timing parameters of the particular SPI memory
device.
TWI master boot from flash takes three input parameters where
R7
is
again the start address and
R6
holds the 7-bit TWI chip select address. If
three address inputs of a TWI memory are named A2, A1 and A0, then
R6
should provide binary
b#1010.A2.A1.A0.x
in its lower byte. In this case,
R5
holds the clock divider value that is written to the
TWI_CLKDIV
register
as shown in the example below.
#include <defBF537.h> /* provides function entry addresses */
P0.H = HI(_BOOTROM_Boot_DXE_TWI) ;
P0.L = LO(_BOOTROM_Boot_DXE_TWI) ;
R7 = 0 (Z) ; /* TWI address is zero */
R6 = 0xA2 (Z) ; /* A2=0, A1=0, A0=1 */
R5 = 0x0811 (Z) ; /* default clock divider */
JUMP (P0) ; /* jump to Boot ROM */
Determining Boot Stream Start Addresses
In some cases the individual boot streams reside at hard coded start
addresses, for example, at page boundaries of flash devices. If multiple
boot streams are generated by a single pass of the Vi+ elfloader
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 ...