"When modifying the pinmux on Orin NX, can I only change configurations that do not trigger warnings?"

Robotics & Edge Computing Jetson Systems Jetson Orin NX
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Customer Usage MCP2518_INT
Pin Direction Input
Req Initial State 空
Wake Pin No
Initiator Target Mode 空
3.3V Tolerance Enable（非常重要）
Int Pull Disable（如果外部已有上拉）
IO Block Voltage 3.3V

I am using BSP 36.5 and want to connect a CAN module via SPI on a custom board to implement CAN functionality. When modifying the pinmux table, I encounter the issue mentioned earlier. Does this mean these pinmux configurations cannot be changed?"

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*** Please note that this reply is generated by LLM automatically ***

The issue you’re encountering is likely due to the pinmux configuration being locked down by the BSP (Board Support Package) version you’re using. In this case, BSP 365.

The pinmux table is a critical component of the Jetson module’s configuration, and it defines how the pins on the module are allocated and used. When you try to modify the pinmux table to connect a CAN module via SPI on your custom board, you’re essentially trying to change the pin allocation.

However, the BSP version you’re using (365) might have already locked down the pinmux configuration, which means that certain pins are reserved for specific functions and cannot be changed.

To resolve this issue, you have a few options:

  1. Check the BSP documentation: Review the BSP documentation to see if there are any specific guidelines or restrictions on modifying the pinmux table. You might need to use a specific version of the BSP or follow certain procedures to make changes to the pinmux configuration.
  2. Use a different BSP version: If possible, try using a different BSP version that might be more flexible with pinmux configuration. However, be aware that changing the BSP version might require significant changes to your software and hardware setup.
  3. Contact NVIDIA support: Reach out to NVIDIA support for assistance with modifying the pinmux table. They might be able to provide guidance on how to make changes to the pinmux configuration or offer alternative solutions.
  4. Consider using a different interface: If modifying the pinmux table is not feasible, you might need to consider using a different interface to connect your CAN module. For example, you could use a USB-to-CAN adapter or a different SPI interface.

In comparison to other Jetson modules, the Jetson Orin NX has a similar pinmux configuration to other modules in the Orin series. However, the specific pinmux configuration might vary depending on the BSP version and the module’s hardware configuration.

To give you a better understanding of the pinmux configuration on the Jetson Orin NX, here is a brief overview of the module’s pinmux table:

  • The Jetson Orin NX has a total of 146 pins, which are allocated for various functions such as GPIO, SPI, I2C, UART, and more.
  • The pinmux table is divided into several sections, including GPIO, SPI, I2C, and UART.
  • Each section has a specific set of pins allocated for that function, and the pinmux configuration defines how those pins are used.

In your case, you’re trying to modify the pinmux table to connect a CAN module via SPI. The SPI interface on the Jetson Orin NX is allocated on pins 33-36, and the pinmux configuration defines how those pins are used.

To modify the pinmux table, you’ll need to use the pinmux tool, which is part of the Jetson Linux Toolchain. The pinmux tool allows you to configure the pinmux table and allocate pins for specific functions.

However, as mentioned earlier, the BSP version you’re using might have already locked down the pinmux configuration, which means that you might not be able to make changes to the pinmux table.

In summary, the issue you’re encountering is likely due to the pinmux configuration being locked down by the BSP version you’re using. To resolve this issue, you’ll need to check the BSP documentation, consider using a different BSP version, contact NVIDIA support, or consider using a different interface to connect your CAN module.

*** Please give the thumbs up if you get answers you like. Or provide feedback to help us improve the answer. ***

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I am using Jetson Orin NX with BSP 36.5 on a custom carrier board.
I want to use an SPI interface to connect an external CAN controller (e.g., MCP2515).
When modifying the pinmux configuration, I receive warnings during boot.

Is this because the SPI pins are configured in MB1 BCT and need to be updated there as well?

What is the correct procedure in L4T R36.x to modify SPI pinmux for a custom board? Hello,
Please find attached our actual hardware schematic.
We are trying to enable SPI for an external CAN controller, but we encounter warnings when modifying the pinmux.
Could you help review the schematic and advise the correct pinmux configuration procedure?

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carolyuu <notifications@nvidia.discoursemail.com> 于2026年2月27日周五 15:25写道：

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Hi 1910884164l,

Are you using MCP2515 or MCP2518FD module?
From the schematic you shared, it seems MCP2518FD.

Pinmux spreadsheet will check if you’ve configured something wrong and show the dialog.
If you connect MCP2518FD module on SPI1, please just configure the SPI function for Customer Usage in pinmux spreadsheet.
I would suggest you verify the SPI loopback test before connecting the module.

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对的是MCP2518FD我想问下这些无法更改的表格内容是不是官方配置好了，我只需要改能动的部分

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Correct, customer should be able to configure Customer Usage, Pin Direction and Req. Initial State.
There’re many logics and error checks in pinmux spreadsheet.