SLAS831D March 2014 – March 2018 PCM1860 , PCM1861 , PCM1862 , PCM1863 , PCM1864 , PCM1865
PRODUCTION DATA.
This function allows post ADC mixing, as well as ADC + incoming I2S mix. Volume control functionality can be performed prior to outputting the signal to an I2S DAC or Amplifier.
Gain range is from –120 dB to +18 dB (4.20 format). Phase Inversion can be done by performing the two's compliment of the positive gain coefficient. two's compliment can be performed by inverting all bits in the binary coefficient, and adding 1 to the LSB.
As the DSP coefficients are directly written, no soft ramping is available. Use of I2S receive sacrifices two digital mic channels due to pin limitations.
Coefficients are written indirectly to virtual memory addresses using the registers on page 1. Details of the registers are shown in the Register Maps section.
A diagram of the digital mixing functionality is shown in Figure 42.