Raspberry Pi I2S DAC Hat
-
I bought this DAC Hat on Kickstarter https://orchardaudio.com/applepi
So I will make a music player. I never wanted a Raspberry Pi, but I have Omega2+. So it hit me - could it be possible to drive
this Raspberry Pi Hat with the Omega2+? Is it possible to make an interface from Omega2+ to the DAC?
-
@Anders-Öster I2S devices are supported in ALSA but currently cause a kernel panic on newer firmware versions.
Refer to https://onion.io/2bt-omega-i2s-audio/ and https://community.onion.io/topic/2910/kernel-panic-with-pulseaudio/.
I still have an open, pending ticket about that kernel panic, making any audio output impossible. You need to manually flash the b177 firmware for it to be usable. (https://docs.onion.io/omega2-docs/manual-firmware-installation.html)
-
Yes I know that I2S is supported since some time now. Didn't know about that kernel issue though. What I wanted to know is if it's possible to use a Raspberry Pi hat with the Omega2+. One would think so. Just connect the correct pins? Or is a driver needed too?
-
I2S in the minimum configuration just needs the bitclock, left-right clock and databits.
According their schematic, these are the exact pins present on the breakout. https://drive.google.com/file/d/1b6Y6fvdK50TgxC3CAdWk2_2lO_vVovy9/view
MCLK is generated on-board with the U13.
There is also an I2C connection, I2C_SDA, I2C_SCL. Probably to configure something? No further schematics are available that show what chip this is connected to from what I've seen.. (here or here)
So either you just need to connec the three I2S pins (data, l-r clock, bitclock), or something important is connected to that I2C bus which I can't find any more info.
-
the DAC appears to need 5v 3amp. the omega2 is ~3v. you will need to account for this and use a level converter at some point.
-
It says on the Kickstarter page that the DAC chip is Burr Brown PCM1794A flagship DACs in monaural mode.
It also says on the Kickstarter page that the ApplePi has a driver built in that Raspbian automatically detects. Maybe that's what I2C is for.
