Managing Clocks
19-4
ADSP-BF535 Blackfin Processor Hardware Reference
Figure 19-1
shows an example clock pin configuration.
All of the core and peripheral clocks are enabled during reset. This
results in a momentary power surge after reset. To avoid this condi-
tion, use the
MSEL
pins to select a lower processor clock (
CCLK
)
speed upon reset. Adjust the clock to the desired operating speed in
the software.
Figure 19-1. External Clock Connections
CLKIN
25 MHz
~
Oscillator
ADSP-BF535
MSEL5 (PF5)
MSEL4 (PF4)
MSEL3 (PF3)
MSEL2 (PF2)
MSEL1 (PF1)
MSEL0 (PF0)
RESET
MSEL6 (PF6)
DF (PF7)
V
DD
V
DD
BYPASS
RESET
SOURCE
RUNTIME
PF PIN I/O
The pull-up/pull-down resis-
tors on the MSEL, SSEL, DF,
and BYPASS pins select the
core and system clock ratio.
The MSEL[6:0] selection and
25 MHz input clock produce a
150 MHz core clock.
Setting SSEL[1:0] to 00
selects a core clock to sys-
tem clock ratio of 2:1. This
produces a 75 MHz system
clock.
SSEL1 (PF9)
SSEL0 (PF8)
Summary of Contents for ADSP-BF535 Blackfin
Page 80: ...Development Tools 1 26 ADSP BF535 Blackfin Processor Hardware Reference...
Page 312: ...Working With Memory 6 86 ADSP BF535 Blackfin Processor Hardware Reference...
Page 332: ...System Interfaces 7 20 ADSP BF535 Blackfin Processor Hardware Reference...
Page 360: ...Dynamic Power Management Controller 8 28 ADSP BF535 Blackfin Processor Hardware Reference...
Page 446: ...Beginning and Ending an SPI Transfer 10 40 ADSP BF535 Blackfin Processor Hardware Reference...
Page 522: ...Timing Examples 11 76 ADSP BF535 Blackfin Processor Hardware Reference...
Page 562: ...IrDA Support 12 40 ADSP BF535 Blackfin Processor Hardware Reference...
Page 608: ...PCI I O Issues 13 46 ADSP BF535 Blackfin Processor Hardware Reference...
Page 672: ...References 14 64 ADSP BF535 Blackfin Processor Hardware Reference...
Page 810: ...SDRAM Controller SDC 18 86 ADSP BF535 Blackfin Processor Hardware Reference...
Page 811: ...ADSP BF535 Blackfin Processor Hardware Reference 18 87 External Bus Interface Unit...
Page 812: ...SDRAM Controller SDC 18 88 ADSP BF535 Blackfin Processor Hardware Reference...
Page 860: ...DMA Bus Debug Registers 20 30 ADSP BF535 Blackfin Processor Hardware Reference...