8 channel audio input in TX2 SOM

Autonomous Machines Jetson & Embedded Systems Jetson TX2
1

Hello,

my question:

Can we design TX2 carrier board in such way that it receives 8 channel audio input ?

The TX2 SOM module datasheet and the Parker SoC datasheet say that only stereo channel is supported.

That is, one I2S input lane and one I2S output lane is supported.

I would like to receive 8 channel audio from HDMI receiver IC.

thanks.

2

I assume you mean i2s (different from i2c)? I also wonder the same thing…how many channels can the J21 connector i2s support?

3

Yes, I2S.

What are the maximum I2S input and output lanes supported in TX2 SOM ?

4

Hi yaluruns,

There are four I2S on TX2, each I2S has its own input and output lane which are DIN/DOUT signals.

5

Trumany,

So each I2S lane can have 2 channel inputs and 2 channel outputs at maximum.

And TX2 SOM does not support 4 channel or 8 channel I2S input or outputs.

Does nvidia have any plan to support 8 channels I2S inputs and outputs in the next version?

We are using TX2 for our broadcasting 4K Encoder, which also supported deep learning.

And we need 8 channel I2S inputs and outputs for broadcasting encoder and decoder usage.

thanks so much.

regards,

6

Each I2S has one input and one output. TX2 has four I2S, so has 4 input and 4 output. You’d better to check the I2S spec to see if it fits your usage.

7

Each I2S has one input and one output. TX2 has four I2S, so has 4 input and 4 output. You’d better to check the I2S spec to see if it fits your usage.

I think it does not satisfy our requirement.

HDMI input can have up to 8 embedded I2S channels. that is, it can have up to 4 I2S lanes.

So we need like followings:

  • 1 bit clock
  • 1 word clock
  • 4 I2S lanes

It seems that TX2 supports following 4 instances.

  • 1 bit clock
  • 1 word clock
  • 1 input lane
  • 1 output lane

regards

8

I would assume each lane actually supports two channels since the word clock alternates left/right. On the other hand, are all lanes available on the developer carrier board? Is it a case where one of the lanes belongs to HDMI?

9

Assume we are using, for example, Silicon Image SiI9233 HDMI receiver IC.

It has pins like followings:

  • 1 bit clock pin
  • word clock pin
  • 4 data lane pins → 8 channels I2S audio

I would like to receive all the 8 channel audio from SiI9233.

But it seems I am able to receive only 2 I2S channels with TX2.

regards,

10

So you are chasing for a I2S port combined with 4 data lane,1 sclk and 1 wclk, right? TX2 does not support that directly although it has four separated I2S ports.

11

So you are chasing for a I2S port combined with 4 data lane,1 sclk and 1 wclk, right?

exactly.

thanks

12

Am I missing something obvious? Each I2S port on TX2 can support up to 16 audio channels bidirectionally, which is called TDM mode. You will need to use AMX and ADX to multiplex/demultiplex these channels in order to get individual channels out to ADMAIF. The whole setup is mentioned in the “Tegra ASoC Driver” section in the L4T documentation, Parker TRM, and implemented in some outdated drivers. I’m working to try to get the driver working, but the hardware clearly can support it without any issue.

13

We cannot utilize TDM because HDMI Receiver IC like SiI9233 does not use TDM mode.

It uses I2S mode using 4 lanes with each lane carrying 2 I2S channels.

regards,

14

@rong1129 Thanks for confirming this.I intend to use it in TDM mode for >8 channels but I am using the Jetson TX2. Can the TX2 also work in TDM mode? I cannot seem to find any documentation for the TX2 similar to what @rong1129 suggested for the JETSON AGX XAVIER.