SLASF34 January 2024 TAC5411-Q1
ADVANCE INFORMATION
The device has an independent programmable channel gain setting for each input channel that can be set to the appropriate value based on the maximum input signal expected in the system and the ADC VREF setting used (see the Section 6.3.5 section), which determines the ADC full-scale signal level.
The device has a programmable digital volume control with a range from –80dB to 47dB in steps of 0.5dB with the option to mute the channel recording. The digital volume control value can be changed dynamically while the ADC channel is powered-up and recording. During volume control changes, the soft ramp-up or ramp-down volume feature is used internally to avoid any audible artifacts. Soft-stepping can be entirely disabled using the ADC_DSP_DISABLE_SOFT_STEP (P0_R114_D1) register bit.
The digital volume control setting is independently available for each output channel, including the digital microphone record channel. However, the device also supports an option to gang-up the volume control setting for all channels together using the channel 1 digital volume control setting, regardless if channel 1 is powered up or powered down. This gang-up can be enabled using the ADC_DSP_DVOL_GANG (P0_R114_D0) register bit.
Table 6-24 shows the programmable options available for the digital volume control.
P0_R82_D[7:0] : ADC_CH1_DVOL[7:0] | DVC SETTING FOR OUTPUT CHANNEL 1 |
---|---|
0000 0000 = 0d | Output channel 1 DVC is set to mute |
0000 0001 = 1d | Output channel 1 DVC is set to –80dB |
0000 0010 = 2d | Output channel 1 DVC is set to –79.5dB |
0000 0011 = 3d | Output channel 1 DVC is set to –79dB |
… | … |
1010 0000 = 160d | Output channel 1 DVC is set to –0.5dB |
1010 0001 = 161d (default) | Output channel 1 DVC is set to 0dB |
1010 0010 = 162d | Output channel 1 DVC is set to 0.5dB |
… | … |
1111 1101 = 253d | Output channel 1 DVC is set to 46dB |
1111 1110 = 254d | Output channel 1 DVC is set to 46.5dB |
1111 1111 = 255d | Output channel 1 DVC is set to 47dB |
Similarly, the digital volume control setting for output channel 2 to channel 4 can be configured using the CH2_DVOL (P0_R87) to CH4_DVOL (P0_R95) register bits, respectively.
The internal digital processing engine soft ramps up the volume from a muted level to the programmed volume level when the channel is powered up, and the internal digital processing engine soft ramps down the volume from a programmed volume to mute when the channel is powered down. This soft-stepping of volume is done to prevent abruptly powering up and powering down the record channel. This feature can also be entirely disabled using the ADC_DSP_DISABLE_SOFT_STEP (P0_R114_D1) register bit.