I have a question/idea/begging helps while I’m utilize I2S output for external DACs.
I’m just making some a ugly and chipper DACs by myself thiking I2S has a lot of merit.
So I simply conntected my es9023 DAC which has it’s own oscillator for MCLK.
And I tried to get any source which shows MCLK support over GPIO of RaspPi, but failed.
Now I have a test with siglechip wm8740 DAC connected to I2S port of RaspPi, which I used a 24.576Mhz SCO to supply MCLK for the DAC chip.
But still having problem to select sample rate, such as multiplying 44.1K or 48K for each different sample rate sources.
Now I just set the resample_rate as 24bit * 192K for fixed MCLK from “MPD.CONF”.
I will try TI’s PLL170X series PLL chip to supply MCLK, but still I need a logic for detect 44.1K or 48K multiplied sample rate.
I’m thinking to use a Atmega 8 to detect sample rate and select the multiplying rate of PLL170X.
Still using a MCU like Atmel or any other(I read a guy did that with PIC Micro chip) is making the project bigger.
So, if somebody can help this I2S dac support having direct MCLK from RaspberryPi or just give a sample rate flag like 0 for 48Ks 1 / 1 for 44.1Ks from one of GPIO, something like that.
It would be very easy programming from MPD variation or snd_5102 XXXX… driver files, but I’m dummy for those kind of stuffs.
It’s just an idea / begging helps. HHH.