Raspberry PI ZERO as USB to I2S Bridge

[JayShoe]

Hello,

Has anyone successfully turned the Raspberry Pi Zero into a USB to I2S Bridge? It most certainly has all the right hardware components to do it. One of the two USB ports can be a USB OTG, and Linux can be configured to be a "Gadget" so that it would be a USB Audio Device.

There is a very interesting article about linux gadgets and ConfigFS (the new "gadget" framework) here: Raspberry Pi Zero as Multiple USB Gadgets << irq5.io

My goal is to use this to send USB Audio signals to the PiDSP... I've posted about this in other threads but I think this warrants a discussion. Any thoughts?

Jay

 

[alonper]

Hi Jay!

I think that link may help you
http://www.peteronion.org.uk/I2S/
I2S Success (at last) ! - Raspberry Pi Forums
Indeed thats not the Pi Zero but I think that we can learn from that project..

BTW I will be happy to collaborate with you,
I am tyring to create a tiny USB-I2S board to operate as a sound card that receives 4 instruments input (high impedance) and stream them to the PC...
So for that point i was just looking for a USB-I2S gate to interface with some ADC,Currently I have the Sparkfun PCM1803A breakout..

 

[JayShoe]

I think that these are helpful for this.

Linux USB gadget configured through configfs


Kernel USB Gadget Configfs Interface by Matt Porter at Linaro

 

[JayShoe]

FYI, this is possible as described here.

lucadentella.it – Raspberry Pi Zero, audio output via I2S

And here
YouTube

 

[DRONE7]

@JayShoe Your links describe a Pi as a player via i2s....yep..they can all do it...easy.

What the o/p wants is a Pi that emulates a usb to i2s bridge.
An xmos or amanero substitute.

Totally different fettle of kish...

 

[JMF11]

For your interest, a different possible hardware are the stm32 nucleo controller boards. They have USB is, multi I2S or SPDIF out...



I did that (with some DSP filtering) in that project Can low jitter be achieved with STM32 microcontroller


For me, this is a quite good hardware for that task



JMF

 

[JayShoe]

@JayShoe Your links describe a Pi as a player via i2s....yep..they can all do it...easy.

What the o/p wants is a Pi that emulates a usb to i2s bridge.
An xmos or amanero substitute.

Totally different fettle of kish...

Lol, I'm the original poster and I just didn't catch the fact that it wasn't to my spec. Yes I'm looking for a "USB Device". This is just playing music on the device itself...

For your interest, a different possible hardware are the stm32 nucleo controller boards. They have USB is, multi I2S or SPDIF out...

I might have to revisit that in the near future. My original intention was to connect the PI Zero to a PiDSP from FreeDSP. The PiZero would be control/usbaudio, and the PiDSP would... DSP. I also had looked into the STM32 NucleoF767ZI development board. In fact, I have one on my desk. I might have to look into Audio Weaver again.

At this point in time what is working for me is the Teensy Audio Bridge Concept. It's much more open than Audio Weaver - which scarred me away with exorbitant commitments.

 

[JMF11]

Hi,

I see that you have done your homework extensively. STm32 is a really good platform with their many audio digital ouputs. Nucleo boards are cool because they expose all pins. I didn't digged Audioweaver deep as it was not free at that time. So great prower, but bare metal: you have to code everything on your own.


JMF