Analog Devices ADSP-BF535 Blackfin, Hardware Reference Manual

Page: 344 / 1022

Dynamic Power Management Controller
8-12 ADSP-BF535 Blackfin Processor Hardware Reference
Operating Modes
The ADSP-BF535 processor operates in four operating modes, each with
unique performance and power saving benefits.
Table 8-3 summarizes the
operational characteristics of each mode.
Full On Mode
Full On is the maximum performance mode of the ADSP-BF535 proces-
sor. In this mode, the PLL is enabled and not bypassed. This is the normal
execution state of the ADSP-BF535 processor, with the processor and all
enabled peripherals running at full speed. In this mode, the input clock
(
CLKIN
) to core clock
(CCLK
) multiplier ratio cannot be changed. DMA
access is available to both L1 and L2 memories. From the Full On mode,
the processor can transition directly to the Active, Sleep or Deep Sleep
modes.
Active Mode
In the Active mode, the PLL is enabled but bypassed. Because the PLL is
bypassed, the processor’s core clock (
CCLK
) runs at one-half the input clock
(
CLKIN
) frequency, offering significant power savings. The system clock
(
SCLK
) frequency is also reduced, because it is derived from
Table 8-3. Operational Characteristics
Operating Mode Power
Savings
PLL
Status Bypassed
CCLK SCLK Allowed
DMA Access
Full On None Enabled No Enabled Enabled L1, L2
Active Medium
Enabled
1
1 PLL can also be disabled in this mode.
Yes Enabled Enabled L1, L2
Sleep High Enabled 2
2 Depends on the previous state.
Disabled Enabled L2
Deep Sleep Maximum Disabled – Disabled Disabled –