TAS2521
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SLAS687A –FEBRUARY 2013–REVISED FEBRUARY 2013
Table 5-3. AVDD LDO Settings
Page-1, Register 2, D(5:4)
00
LDO Output
1.8 V
01
10
00
1.6 V
1.7 V
1.5 V
For more detailed information see the TAS2521 Application Reference Guide (SLAU456).
5.6.5 POR
TAS2521 has a POR (Power On Reset) function. This function insures that all registers are automatically
set to defaults when a proper power up sequence is executed.
For more detailed information see the TAS2521 Application Reference Guide (SLAU456).
5.6.6 CLOCK Generation and PLL
The TAS2521 supports a wide range of options for generating clocks for the DAC sections as well as
interface and other control blocks. The clocks for the DAC require a source reference clock. This clock can
be provided on a variety of device pins, such as the MCLK, BCLK, or GPIO pins. The source reference
clock for the codec can be chosen by programming the CODEC_CLKIN value on page 0, register 4, bits
D1–D0. The CODEC_CLKIN can then be routed through highly-flexible clock dividers shown in to
generate the various clocks required for the DAC and the miniDSP section. In the event that the desired
audio clocks cannot be generated from the reference clocks on MCLK, BCLK, or GPIO, the TAS2521 also
provides the option of using the on-chip PLL which supports a wide range of fractional multiplication
values to generate the required clocks. Starting from CODEC_CLKIN, the TAS2521 provides several
programmable clock dividers to help achieve a variety of sampling rates for the DAC and clocks for the
miniDSP sections.
For more detailed information see the TAS2521 Application Reference Guide (SLAU456).
5.6.7 Digital Audio and Control Interface
5.6.7.1 Digital Audio Interface
Audio data is transferred between the host processor and the TAS2521 via the digital audio data serial
interface, or audio bus. The audio bus on this device is flexible, including left- or right-justified data
options, support for I2S or PCM protocols, programmable data-length options, a TDM mode for
multichannel operation, flexible master/slave configurability for each bus clock line, and the ability to
communicate with multiple devices within a system directly.
The audio bus of the TAS2521 can be configured for left- or right-justified, I2S, DSP, or TDM modes of
operation, where communication with standard telephony PCM interfaces is supported within the TDM
mode. These modes are all MSB-first, with data width programmable as 16, 20, 24, or 32 bits by
configuring page 0, register 27, bits D5–D4. In addition, the word clock and bit clock can be independently
configured in either master or slave mode for flexible connectivity to a wide variety of processors. The
word clock is used to define the beginning of a frame, and may be programmed as either a pulse or a
square-wave signal. The frequency of this clock corresponds to the maximum of the selected DAC
sampling frequencies.
For more detailed information see the TAS2521 Application Reference Guide (SLAU456).
5.6.7.2 Control Interface
The TAS2521 control interface supports SPI or I2C communication protocols, with the protocol selectable
using the SPI_SEL pin. For SPI, SPI_SEL should be tied high; for I2C, SPI_SEL should be tied low. It is
not recommended to change the state of SPI_SEL during device operation.
Copyright © 2013, Texas Instruments Incorporated
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