I2S vs TDM requirement for ADAU7118 with 6 digital microphones on RK3588

SigmaDSP & SigmaStudio Phong Feb 10, 2026 00:00 2 replies Original on forum ↗

Thread Summary

The user asked if standard I2S is sufficient for transmitting audio from 6 digital microphones (IM66D130AXTMA1) through the ADAU7118ACPZRL codec to the Rockchip RK3588 processor. The engineer confirmed that TDM is required to handle more than two channels and suggested configuring the ADAU7118 in TDM-6 mode, sending zeros on the two unused slots, as the RK3588 operates in TDM-8 mode.
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Phong Question

Feb 10, 2026 00:00

Dear ADI team,

I would like to ask for clarification regarding the audio interface selection for the following architecture:

Processor: Rockchip RK3588 (CM3588)
Audio codec / DSP: ADAU7118ACPZRL
Microphones: 6 × IM66D130AXTMA1 (digital microphones)

My question is:

With this architecture, do I need to use I2S with TDM support, or is standard I2S (non-TDM) sufficient?

Since I am using 6 digital microphones connected through the ADAU7118, I would like to confirm whether TDM is mandatory to transmit all microphone channels to the RK3588, or if there is an alternative configuration using standard I2S.

Thank you.

Edit Notes
Update with additional datasheet images.

[edited by: Phong at 4:05 PM (GMT -5) on 11 Feb 2026]

hardware

Integrated/Special Purpose A/D Converters

Audio A/D Converters

ADAU7118

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DaveThib Reply

Feb 11, 2026 00:00

Hello Phong,

This is a small low cost part so we could not add a bunch of extra pins that are usually not needed or used. So there is only one SDATA Output pin. So you cannot output three different I2S serial data formats on three different pins. You have to use TDM to send out up to eight channels.

Now, the TDM format is rather flexible. As soon as the next frame pulse is received it will start back with sending out the data assigned to slot 0. So therefore, you could setup a TDM-6 format where it sends out six channels then resets and starts sending the next sample period frame's data. In the datasheet I mentioned it could be a little as one channel!

So the basic answer to your question is Yes, you have to use TDM to send more than two channels.

Based on what you posted, It looks to me that the RK3588 only operates in TDM-8 mode which is fine. You can setup the ADAU7118 to just send zeros on the last two unused slots.