Datasheet

ADAU1772 Data Sheet
Rev. B | Page 44 of 116
MULTIPURPOSE PINS
The ADAU1772 has seven multipurpose (MP) pins that can be
used for serial data I/O, clock outputs, and control in a system
without a microcontroller. Each pin can be individually set to
either its default or MP setting. The functions include push-
button volume controls, enabling the compressors, parameter
bank switching, DSP bypass mode, and muting the outputs.
The function of each of these pins is set in Register 0x0038 to
Register 0x003E. By default, each pin is configured as an input.
Table 26. Multipurpose Pin Functions
Pin No. Default Pin Function Secondary Pin Functions
31 LRCLK Multipurpose control inputs
32
BCLK
Multipurpose control inputs
33 DAC_SDATA Multipurpose control inputs
34 MP1 acting as push-
button volume up
ADC_SDATA0, PDM output,
multipurpose control inputs
35 MP6 acting as push-
button volume down
ADC_SDATA1, CLKOUT,
multipurpose control inputs
36 DMIC2_3 Multipurpose control inputs
37 DMIC0_1 Multipurpose control inputs
PUSH-BUTTON VOLUME CONTROLS
The ADC and DAC volume controls can be set up to be controlled
with two push-buttons—one for volume up and one for volume
down. The volume setting can either be changed with a click of the
button or be ramped by holding the button. The volume settings
change when the signal on the pin from the button goes from
low to high.
When in push-button mode, the initial volume level is set with
Bits PB_VOL_INIT_VAL. By default, MP1 acts as the push-
button volume up and MP6 acts as the push-button volume
down; however, any of the MPx pins can be set to act as the
push-button up and push-button down volume controls.
When the ADC and/or DAC volumes are controlled with the
push-buttons, the corresponding volume control registers no
longer allow control of the volume from the control port.
Therefore, writing to these volume control registers has no
effect on the codec volume level.
LIMITER COMPRESSION ENABLE
This function allows a user to enable limiter compression
regardless of the signal level. Setting an MPx pin low when this
function is enabled causes the limiter to compress the incoming
signal by the minimum gain setting. When the MPx pin is released,
the limiter resumes normal behavior.
PARAMETER BANK SWITCHING
An MPx pin can be used to switch the active parameter bank
between Bank A and Bank B. When this setting is selected,
Bank A is active when the pin is high and Bank B is active when
the pin is low. Care should be taken to set the BANK_SL bits in
the CORE_CONTROL register (Address 0x0009) to the default
value of 0x00 before enabling MPx pin control over bank
switching. Simultaneous control of bank switching by both
register setting and MPx pin selection is not possible.
Bit ZERO_STATE selects whether the data memory of the
codec is set to 0 during a bank switch. If the data is not set to 0
when a new set of filter coefficients is enabled via a bank switch,
there may be a pop in the audio as the old data is circulated in
the new filters.
MUTE
The MPx pins can be put into a mode to mute the ADCs or DACs.
When in this mode, mute is enabled when an MPx pin is set low.
The full combination of possible mutes for ADCs and DACs
using MPx pins are set in Register 0x0038 to Register 0x003E.