Datasheet

TLV320DAC3100
SLAS671A –FEBRUARY 2010–REVISED MAY 2012 www.ti.com
NOTES:
1. f
in
should be less than f
S
/4.
2. For the sine and cosine values, if the number of bits is less than the full 16-bit value, then the unused
MSBs must be written as 0s.
3. For the beep-length values, if number of bits is less than the full 24-bit value, then the unused MSBs
must be written as 0s.
Following the beep-volume control is a digital mixer that mixes in a playback data stream whose level has
already been set by the DAC volume control. Therefore, once the key-click volume level is set, the key-
click volume is not affected by the DAC volume control, which is the main control available to the end
user. This functionality is shown in Figure 1-1.
Following the DAC, the signal can be further scaled by the analog output volume control and power-
amplifier level control.
The beep generator is used for the key-click function. A single beep is generated by writing to page 0 /
register 71, bit D7. After the programmed beep length has finished, register 71, bit D7 is reset back to
zero.
5.5.8 Programming DAC Digital Filter Coefficients
The digital filter coefficients must be programmed through the I
2
C interface. All digital filtering for the DAC
signal path must be loaded into the RAM before the DAC is powered on. (Note that default ALLPASS filter
coefficients for programmable biquads are located in boot ROM. The boot ROM automatically loads the
default values into the RAM following a hardware reset (toggling the RESET pin) or after a software reset.
After resetting the device, loading boot ROM coefficients into the digital filters requires 100 μs of
programming time. During this time, reading or writing to page 8 through page 15 for updating DAC filter
coefficient values is not permitted. (The DAC should not be powered up until after all of the DAC
configurations have been initialized by the system microprocessor.)
5.5.9 Updating DAC Digital Filter Coefficients During PLAY
When it is required to update the DAC digital filter coefficients or beep generator during play, care must be
taken to avoid click and pop noise or even a possible oscillation noise. These artifacts can occur if the
DAC coefficients are updated without following the proper update sequence. The correct sequence is
shown in Figure 5-19. The values for times listed in Figure 5-19 are conservative and should be used for
software purposes.
There is also an adaptive mode, in which DAC coefficients can be updated while the DAC is on. For
details, see Section 5.5.1.3.
38 APPLICATION INFORMATION Copyright © 2010–2012, Texas Instruments Incorporated
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