Jetson TX2 Devkit How can we access I2S5 interface on J26 (30 pin expansion header)

Autonomous Machines Jetson & Embedded Systems Jetson TX2
1

Hi,

We are doing a development on the TX2 devkit where we want to access 4 I2S interfaces connected to 4 separate audio codecs.

Based on the information in the developers guide we planned to use the following I2S interfaces:

image
image1369×659 18.3 KB

Interface Location
I2S1 40 pin header (J21)
I2S2 30 pin header (via DAP2 pins) (J26)
I2S5 30 pin header (via DAP5 pins) (J26)
I2S3 M2.KeyE connector (via DAP3 pins)

The problem we have is that we cant find any reference in the documentation on how to access I2S5? It does not seem to be mentioned in the document JetsonTX1_TX2_Developer_Kit_Carrier_Board_Specification1.pdf

Please can you point me to the relevant information?
Can this interface actually be accessed as the developer documentation suggests?

Thanks

Dom

3

Hello Dom!

If you download the Jetson TX1 and TX2 Developer Kit carrier board design files you should fine the schematic for the carrier board inside in a doc called ‘P2597_C02_Concept_schematics.pdf’. In this document, you can find the pinout of the 30-pin header J26 on page 16. And yes you can access and use this interface. Please note that this interface operates at 1.8V. By default the I2S1 operates are 3.3V via a level shifter which can be change to 1.8V by jumper J24 (also see page 16 in the schematic). We have tested I2S5 by jumper wiring it to I2S1 and operating I2S1 at 1.8V.

Regards
Jon

4

Hi Jon,

Thanks for your reply. The confusion for us is that the documentation (see the picture I pasted extracted from the developer guide) suggests that there should be 2 x I2S interfaces available on J26? I2S2 via the DAP2 pins and I2S5 via the DAP5 pins, but we can only see the one.

I have just looked at the schematic again, and please can I check with you that there are actually only 4 I2S interfaces accessable on the devkit as follows:

CVM 1,0 (J13), Connector, DAP Pins
I2S0, J21 40 pin GPIO, DAP1
I2S1, J26 30 pin GPIO, DAP5
I2S2, M.2 KEY E, DAP3
I2S3, J22 Camera, DAP4

The second interface I2S2 (via DAP2 pins) on J26 mentioned in the documentation, doesn’t actually seem to exist?

kind regards

Dom

5

Hi Dom,

Sorry, I see what you are saying. Yes that looks like a bug in the documentation. Only I2S2 is available on the 30-pin header. For TX1 I2S5 is available on the 30-pin header and for TX2 it is I2S2. I recall that we used the I2S interface on the 30-pin header for testing loopback but on TX2 that would have been I2S2 and not I2S5 as I previously mentioned.

For TX2 there are 4 I2S interfaces available which are:

  1. I2S1 40-pin header (J21)
  2. I2S2 30-pin header (J26)
  3. I2S3 M.2 Key E slot
  4. I2S4 Camera header (J22)

Please note that the TX2 module itself exposes all 6 I2S interfaces. I will file a bug to get the documentation fixed for TX2.

Regards,
Jon

6

Hi Jon,

Thanks for the clarification! We were going round in circles a bit here trying to work it out.

Regards

Dom