Modifying AGX Xavier PinMux for 3rd party carrier board

I have to configure I2S3_SCLK, I2S3_DOUT, I2S3_DIN, and I2S3_FS as GPIO inputs on a 3rd party carrier board. I’ve never done anything like this and I’m quite confused by the documentation. I have the following questions:

  1. From the pinmux configuration template I can find the pin #, however, I’m not sure how to identify the MPIO Pad Type (ST, CZ, DD, LV_CZ). I tried searching the TRM and the datasheet to no avail;
  2. Do I have to change the .cfg file on the host and re-flash the board (as shown in this example on eLinux), or can I work directly on the device (which is, as far as I understand, what jetson-io does for the DevKit)?
  3. From what I understand from section 8.5.3.1 PinMux programming in the TRM, it looks like that the function of certain pins can be changed programmatically on the fly. Is that an alternative to changing the static PinMux configuration?

hello andrea,

it’s board configuration file, i.e. tegra19x-mb1-pinmux-p2888-0000-a04-p2822-0000-b01.cfg to include the pin configuration and flashed to the target.
after that, you may able to update the pin configuration through device tree overlay, i.e. *.dtbo, there’s Jetson-IO utility to simplify the configuration. please also check developer guide for reference, Configuring the 40-Pin Expansion Header.
please also access Xavier Product Design Guide and please check [Table 12-1. Jetson AGX Xavier Audio Pin Description] for reference.
thanks

Hi @JerryChang, thank you for your support. I need to do this for a 3rd party carrier board, so I can’t use the Jetson-IO, as far as I understand.

How about my first question? How do I find the MPIO Pad Type (ST, CZ, DD, LV_CZ) for specific pads?

hello andrea,

please access Jetson AGX Xavier Series Pinmux and check the [Pad Category] for reference.
please also refer to Jetson AGX Xavier Series Module Data Sheet, see [Chapter 16. Pads] for more details.
thanks

1 Like

@JerryChang I finally found the Pad Info columns in the spreadsheet. For some reasons they are hidden by default. However, I’m not sure about the second document, as there’s no Chapter 16 in the data sheet.

hello andrea,

it should be Jetson AGX Xavier Series OEM Product Design Guide , see page-135 for the Pads chapter.
thanks

1 Like