ADSP-BF523C AD [Analog Devices], ADSP-BF523C Datasheet - Page 26

• Manufacturer Part Number: ADSP-BF523C
• Description: Blackfin Embedded Processor 289-ball MBGA package
• Manufacturer: AD [Analog Devices]

ADSP-BF523C/ADSP-BF525C/ADSP-BF527C
The power down control can be used to permanently disable
functions when not required in certain applications. Or the
modes can be used to dynamically power functions up and
down depending on the operating mode, for example during
playback or record. If dynamic implementations are used, the
special instructions in the following sections should be followed.
LINEINPD
Simultaneously powers down both line inputs. This can be done
dynamically without audible effects either on the ADC or on the
line outputs in bypass mode. This is useful when the device
enters playback, pause or stop modes or when the microphone
input is selected.
MICPD
Simultaneously powers down both the microphone input and
the microphone bias. If this is done dynamically audible pops
through the ADC will result, but they will only be audible if the
microphone input is selected to the ADC at the time. If the state
of MICPD is changed, the controlling processor should switch
the line inputs to the ADC (INSEL) before changing MICPD.
This is useful when the device enters playback, pause or stop
modes or when the microphone input is not selected.
ADCPD
Powers down the ADC and ADC filters. If this is done dynami-
cally audible pops will result if any signals were passing through
the ADC. To avoid popping when the ADC is to be powered
down, either mute the microphone input (MUTEIN) or mute
the MUTELINEIN, then change ADCPD. This is useful when
the device enters playback, pause or stop modes regardless
whether microphone or line inputs are selected.
DACPD
Powers down the DAC and DAC digital filters. If this is done
dynamically audible pops will result. To prevent pop—the DAC
should first be soft-muted (DACMU), then the output should
be de-selected from the line and headphone output (DACSEL),
and then the DAC powered down (DACPD). This is useful
when the device enters record, pause, stop or bypass modes.
OUTPD
Powers down the line and headphone outputs. If this is done
dynamically audible pops may result unless the DAC is first
soft-muted (DACMU). This is useful when the device enters
record, pause or stop modes.
OSCPD
Powers off the on board crystal oscillator. The CODEC_MCLK
input functions independently of the oscillator being powered
down.
CLKOUTPD
Powers down the CODEC_CLKOUT pin. This conserves power
and reduces digital noise and RF emissions. CODEC_CLKOUT
is tied low when powered down.
Rev. PrC | Page 26 of 44 | June 2008
Standby Mode
The device can be put into a standby mode by powering down
all the audio circuitry using the software control shown in
Table
are being used to derive the master clock, the crystal oscillator
can be powered off without powering off CODEC_CLKOUT.
Table 26. Standby Mode
In standby mode the control interface, and a small portion of
the digital and areas of the analog circuitry remain active. The
active analog includes the analog VMID reference so that the
analog line inputs, line outputs and headphone outputs remain
biased to VMID. This reduces audible effects from dc glitches
when entering or leaving standby mode.
Power Off Mode
The device can be powered off by writing to the POWEROFF bit
of the power down register. In the power off mode, the control
interface and a small portion of the digital circuits remain
active. The analog VMID reference is disabled. As in standby
mode, the crystal oscillator and/or CODEC_CLKOUT pin can
be independently controlled. See
Table 27. Poweroff Mode
0
0
0
1
1
1
0
1
1
0
1
1
26. If the crystal oscillator and/or CODEC_CLKOUT pins
0
0
1
0
0
1
1
1
1
X
X
X
1
1
1
X
X
X
Preliminary Technical Data
1
1
1
X
X
X
1
1
1
X
X
X
1
1
1
X
X
X
Description
STANDBY, with Crystal Oscillator
and CODEC_CLKOUT available
STANDBY, with Crystal Oscillator
available, CODEC_CLKOUT not
available
STANDBY, Crystal Oscillator and
CODEC_CLKOUT not available.
Description
POWEROFF,
with Crystal Oscillator and
CODEC_CLKOUT available
POWEROFF,
with Crystal Oscillator available,
CODEC_CLKOUT not available
POWEROFF,
Crystal Oscillator and
CODEC_CLKOUT not available
Table
27.