Minimum requirements for Walkie Talkie DEMO

[Jorritv3]

Hi,

I am working on a PCB with the nrf5340 and I have been following the reference schematics and the hardware files from the audio DK. I want to have the bare minimum required to run the Walkie Talkie Demo. I now have the VM3011 as microphone connected to the nrf5340 according to the schematics, and also to the CS47L63 for the audio processing. I connected the I2S pins from the nrf5340 to the CS47L63. 

Now I want to know if this is everything needed to get it working or if I am still missing some (or a lot of) pieces. Of course the audio would still need to go somewhere, but I will implement a small speaker instead of a headphone plug, but in general:

Is only an audio DSP, a microphone, an nrf5340, and a speaker enough to get the walkie talkie demo working on a custom build?

Lastly I am also confused on how to power this because in the schematics I see the Audio DK using a nPM1100, but in the documentation it says the battery can be directly connectd to VDDH?
I built my design around reference circuitry no.1 for QKAA aQFN94 and plan on using a simple coin cell for powering.

[Hieu]

Hi Jorritv3,

Is only an audio DSP, a microphone, an nrf5340, and a speaker enough to get the walkie talkie demo working on a custom build?

Technically, yes. If you want to use the nRF5340 Audio Application directly without any modification, I recommend referring to the nRF5340 Audio DK's HW documentation and design files and replicate it, down to the pin selection.

Otherwise, the nRF5340 Audio Application is meant to be a reference/sample. You should be able to modify it to your exact need.

Lastly I am also confused on how to power this because in the schematics I see the Audio DK using a nPM1100, but in the documentation it says the battery can be directly connectd to VDDH?
I built my design around reference circuitry no.1 for QKAA aQFN94 and plan on using a simple coin cell for powering.

I am lacking the context of the documentation you are referring to. However, refer to the Block Diagram in the nRF5340 Audio DK documentation, you can see that it accepts both a battery or USB as power source.

The Walkie Talkie demo has the nRF5340 run LE Audio in Connected Isochronous Stream (CIS) mode. While this can be a little less power consuming than the Broadcast Isochronous Stream (BIS) mode, it is still quite power consuming. 
I recommend you use the nRF5340 Audio DK to perform some measurements and refer to the datasheets of the other components to have a rough calculation of expected lifetime.

Hieu

[Jorritv3]

Thank you for the answer.

I am still a bit confused.

because of this regulators documentation I thought the battery could be directly connected to the nrf5340 chip, but in the audio dk design files a npm1100 is used. Is this strictly required, or can I hook up a battery directly?

[Bendik Heiskel]

Hi,

If the battery is in the range 1.7V to 3.6V you can connect it directly to the nRF5340 and configure the regulators for normal voltage mode, VDD and VDDH shorted together, if the battery is within 2.5-5.5V you can also connect it directly to the nRF5340 in high voltage mode, battery connected to just VDDH.

Coincell batteries are usually 3V so using the normal voltage mode is probably best in your use case.

 

The Audio DK is using the nPM1100 because it support rechargeable lithium batteries. the nPM1100 does not support primary cell batteries, so if you still want to use a PMIC you can look into using the nPM2100.

 

Best regards,

Bendik