Finding I2S pins in nRF5340 DK

[alpereira7]

Hi,

I'm trying to find the I2S pins on the nRF5340 DK board, in order to connect an external hardware codec.

I've read nRF5340 product brief, and it specifies I2S compatible, however I don't find any reference of I2S in nRF5340 DK Hardware user guide. I know I can find nRK5340 Audio DK, but it is unavailable and I'd like to use nRF5340 DK.

Can you help me find the right pins in nRF5340 DK?

[Jared]

Hi,

Are you using a specific example? The I2S peripheral doesn't have dedicated pins, it can use any available GPIO pin.

regards

Jared 

[alpereira7]

I'm trying to use the nRF5340 Audio example in the nRF5340 DK board. I'm trying to find where are the I2S pins are so I can connect an external codec.

By looking at the nrf5340 audio example, I can't find where the I2S or GPIO pins are defined.

After reading nRF5340 Product Specification p.253, I was trying to find similarities with nrf5340 audio example to find where are the i2S pin configuration is located, but couldn't find anything similar (e.g. NRF_I2S structure, PSEL.LRCK, PSEL.SCK... none of these keywords returned anything).

[Jared]

Hi,

Which board did you build the example for, and did it build successfully? Are you using the same encoder as on the audio kit? 

Can you share your build folder?

regards

Jared 

[alpereira7]

I'm building the example with the nRF5340 DK board. I don't have connected the hardware codec, I'm trying to identify what are the pins I need to connect the codec to (which is my main question). It is not the same codec as in the nRF5340 Audio DK board.

It build and flashed without notifying any error.

I'm not sure I can share the build folder, I need to check if there is no critical information first. What are we looking for in that folder?

Thanks.

[Jared]

any available GPIO pin can be used for the I2S peripheral. If you're using the audio application then it will use specific pins set by the application, if you share your build folder then I can check which pins that are assigned for the I2S peripheral and answer your main question or you can go into the build folder and check Zephyr.dts and see which pins are assigned to the I2S peripheral. 

If it's not the same codec then you probably need to either create a new driver or check and see if that codec already has a driver in zephyr. It wont be as easy as just building the application and connect the codec.

regards

Jared 

[alpereira7]

5633.zephyr.dts

Please, see the zephyr.dts file that was in nrf5340_audio/build/zephyr/. So far I can't found any information related to LRCK, SCK, SDIN, SDOUT, maybe you can find something...

build folder is 100 Mbytes, after zipped is 24 Mbyte which seems too big to attach here.

[Jared]

Hi,

It looks like the pins that are used are P0.12,  P0.14, P0.16, P0,13, P0.15 which seems to be the same as in the schematic for the audio DK:

You can also double check this by using the debugger and pausing the application after initializing the I2S peripheral and see what pins that are selected in the PSEL registers.

regards

Jared