SLAS831D March 2014 – March 2018 PCM1860 , PCM1861 , PCM1862 , PCM1863 , PCM1864 , PCM1865
PRODUCTION DATA.
This function is used for external analog controls, such as potentiometers to set volume, tone control, or a sensor. The data for control sense has no high pass filter applied to it, even if the main audio path does have a HPF enabled.
AS shown in Figure 36, there are two parameters for the dc level change detection: reference level (REF_LEVEL) and difference level (DIFF_LEVEL). Each input pin (input 1 through 8) has a different reference and difference level.
Users set a reference point, and a difference point. If the voltage at the control point crosses the difference point then an interrupt is driven from the device. This is useful for filtering out noise, as well as reducing the load on the host processor for controls that tend to be set and forget (such as volume).
The data from the secondary ADC can also be streamed out of the device in TDM form and directly from the I2C register map. AUXADC_DATA_CTRL (Page.0 0x58) is used to configure and check the status of the DC detector.
This feature (thresholds and interrupts) is available in both active and sleep modes. In sleep mode, the device automatically scans through each channel designated a controlsense input. In active mode, the scanning will need to be done manually by a host microcontroller by modifying the SEC_ADC_INPUT_SEL (Page.0, 0x0A) register.
Most applications requiring the use of a potentiometer for control can simply use the SIGDET_DC_LEVEL_CHx_x registers to read the 8-bit value. To enable the SIGDET_DC_LEVEL_CHx_x registers to work, then the DC_NOLATCH AUXADC_DATA_CTRL (Page.0, 0x58, B[7]) should be set to 1, and the appropriate input pins should be set to controlsense inputs SIGDET_CH_MODE (Page.0, 0x30)
Direct 16-bit two's compliment reads from the secondary ADC can be done using AUXADC_DATA_CTRL (Page.0, 0x58) includes a latch function that is used to read the data the secondary ADC on demand in 16-bit two's compliment format from registers 0x59 and 0x5A.