SLAAEH2 December   2023 TAA5212 , TAC5111 , TAC5112 , TAC5211 , TAC5212 , TAD5112 , TAD5212

 

  1.   1
  2.   Abstract
  3.   Trademarks
  4. 1Introduction
  5. 2TAx5x1x Audio Serial Interface
  6. 3TAx5x1x Synchronous Sampling Rate Converter
    1. 3.1 ADC Sampling Rate Conversion
    2. 3.2 DAC Sampling Rate Conversion
    3. 3.3 SRC Use Case Examples
      1. 3.3.1 Default Mode (Main Fs - Higher rate)
      2. 3.3.2 Default Mode (Main Fs - Higher rate) with Recording
      3. 3.3.3 Custom Mode (Main Fs - Lower rate)
      4. 3.3.4 Custom Mode (Main Fs - Lower rate) with Recording
  7. 4Summary
  8. 5References

3.2 DAC Sampling Rate Conversion

In DAC SRC flow, the received ASI bus can pass through the Sampling Rate Converter first as mixing or muxing can run at the main Fs rate. The default DAC flow is shown in Figure 3-2 where 2 ASI digital inputs running at different sampling rates are mixed/muxed before any digital filtering, volume control, interpolation and DAC drivers. Similar to the ADC SRC, user can choose Primary ASI or Secondary ASI for the two rates. Figure 3-2 shows main Fs as the higher rate (default mode).

GUID-20231024-SS0I-H4ZJ-SBVS-5H4BM0HZ9XCS-low.pngFigure 3-2 TAx5x1x DAC SRC Overview - Default Mode

Similar to ADC, the user needs to watch the levels when mixing 2 signals and the equation to set the mixing coefficients for DAC is given below where w represents the weight or scale of magnitude. For example w=0.5 represents half of the magnitude which translates into 'h2000 in the 16-bit DAC mixer coefficients. The default on some of the path coefficients are 'h4000 for the full scale magnitude of 1.

Equation 4. Coeff(hex) =hex(214 × w)

The DAC mixer coefficients are configured through register page address 0x11 register address 0x08 to 0x47 for main ASI (higher rate interface) and for auxiliary ASI (lower rate), it's configured through register page address 0x11 register address 0x48 to 0x57.

For Side Chain DAC mixer, the coefficients are configured through register page address 0x11 and register address from 0x58 to 0x77 using the same coefficient Equation 4.