Dear Technical support team,
My objective is, I need to use the external clock source to supply the system clock to Audio DAC after SRC4392.
I must know the exact Sampling Frequency Rate (Fs) of audio data that encoded from SPDIF source. To determine the Fs, refer to the reference from datasheet on below, it seems SRC4392 can't provide exactly sampling frequency rate becasue the information from register 0x13 just tell us the Maximum Available RXCKO Rate. If RXCKR1 and RXCKR0 bit is 1 and 1, repectively, the Maximum Available RXCKO Rate is 512*Fs. It means RXCKO can be 512*Fs or 256*fS or 128*fS or etc.
So the question is, how can I excatly know the Sampling Frequency Rate from original source?
Reference:"The 16fS clock is then processed by PLL2, which further multiplies the clock rate and provides low-pass filtering for jitter attenuation. The available PLL2 output clock rates include 512fS, 256fS, and 128fS. The maximum available PLL2 output clock rate for a given input sampling rate is estimated by internal logic and made available for readback via status register 0x13."
and
"Maximum Available Recovered Clock Rate
These two bits indicate the maximum available RXCKO clock rate based upon the DIR detection circuitry, which determines the frame rate
of the incoming AES3-encoded bit stream. Based upon the estimated frame rate, a maximum rate for the recovered clock output (RXCKO)
is determined and output from PLL2, as well as being loaded into the RXCKR0 and RXCKR1 status bits.
The status of the RXCKR0 and RXCKR1 bits may be utilized to determine the programmed value for the PLL2 output clock divider, set by
the RXCKOD0 and RXCKOD1 bits in control register 0x0E.
RXCKR1 RXCKR0 Maximum Available RXCKO Rate
0 0 Clock rate not determined.
0 1 128fS
1 0 256fS
1 1 512fS "
Best regards,
Kamorn.
