Dynamic Power Management Controller
20-22
ADSP-BF537 Blackfin Processor Hardware Reference
After changing the voltage level in the
VR_CTL
register, the PLL automati-
cally enters the active mode when the processor enters the idle state. At
that point the voltage level changes and the PLL relocks with the new volt-
age. After the
PLL_LOCKCNT
has expired, the part returns to the full on
state. When changing voltages, a larger
PLL_LOCKCNT
value may be neces-
sary than when changing just the PLL frequency. See the processor data
sheet for details.
After the voltage has been changed to the new level, the processor can
safely return to any operational mode so long as the operating parameters,
such as core clock frequency (
CCLK
), are within the limits specified in the
processor data sheet for the new operating voltage level.
Powering Down the Core (Hibernate State)
The internal supply regulator for the processor can be shut off by writing
b#00
to the
FREQ
bits of the
VR_CTL
register. This disables both
CCLK
and
SCLK
. Furthermore, it sets the internal power supply voltage (V
DDINT
) to
0 V, eliminating any leakage currents from the processor. The internal
supply regulator can be woken up by several user-selectable events, all of
which are controlled in the
VR_CTL
register:
• RTC event or assertion of the
RESET
pin. Set the wakeup-enable
(
WAKE
) control bit. This bit must be set if no other wakeups are
enabled.
• External GP event, or PHY event (ADSP-BF536 or ADSP-BF537
only, if PHY is used). On the ADSP-BF536 and ADSP-BF537
Blackfin processors, set the PHY wakeup enable (
PHYWE
) control bit
1110
1.25 volts
1111
1.30 volts
Table 20-10. VLEV Encodings (Cont’d)
VLEV
Voltage
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 ...