Access to I2S interface on nRF5340 Audio DK

[colindente]

Hi,

I have two nRF5340 Audio DKs which I can successfully configure and use to send BLE audio between them.  I would like to send audio data from my own development board to an I2S interface on the "gateway" DK, but the SDK seems to only allow you to configure it to use I2S input from the on-board codec.

There are likely-looking pin labels on P10 and P11, but these do not carry the I2S signals from the codec (which appear to be visible on P5).  Can you tell me how to configure the device so that I can inject I2S data through P10 or P11?

Regards,

Colin Dente 

[Bendik Heiskel]

Hi Colin,

There I2S routing is controlled by a onboard switch, the default connection is to the onboard codec. GPIO pin P0.21 must be set high to switch to the external I2S connection on P10.

 

Best regards,

Bendik

[colindente]

Hi Bendik,

Thanks for the quick reply.  Can you tell me where in the nRF Connect SDK code I can set this GPIO?

Colin

[Bendik Heiskel]

The pin must be set at the start of main. This can be done using either the Zephyr GPIO driver or the nrfx GPIO driver.

How to use the Zephyr GPIO driver is covered by the Nordic Developer Academy.

To use the nrfx GPIO driver all you need to do is:

#include <hal/nrf_gpio.h>

And at the start of main:

nrf_gpio_cfg_output(21);
nrf_gpio_pin_set(21);

Best regards,

Bendik

[colindente]

Thanks Bendik,

That's exactly what I wanted to know.  You've been very helpful.

Regards,

Colin

[max.proskauer]

I'm in a very similar situation. I was able to configure my gateway board to accept external I2S as described in the reply from Bendik Heiskel . Note that for me at least, the call to set GPIO P0.21 high needed to happen AFTER the call to `audio_system_init()`. If your configuration is correct, the green CODEC LED near the headphone jack will be OFF and the OB/EXT LED near P10 will be ORANGE

I also added the `CONFIG_AUDIO_SOURCE_I2S=y` line to my project .conf file as described in the README for the nrf5340_audio project.

The issue that I am encountering now is that the nRF board is still acting as the I2S master. The other device I want to connect I am not in control of and is configured as an I2S master. I need the nRF board to act as I2S slave and transmit the audio the other device is sending it over the Bluetooth link (in my case as a BIS broadcast). How can I configure the nRF as I2S slave?