SPI IC flashing for Realtek RTS5420

Robotics & Edge Computing Jetson Systems Jetson Orin NX
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We have developed a custom carrier board for the Orin NX following NVIDIA’s product design guidelines. For the USB 3.2 super speed hub, NVIDIA recommends using the Realtek RTS5420, which we are using successfully.

My question is regarding the SPI flash connected to the Realtek RTS5420. Based on the available documentation, the SPI flash is used to store the RTS5420 configuration and is programmable. We have included the required SPI flash IC on our board, but we are not explicitly programming or flashing it.

So, how is the USB hub functioning without flashing the SPI flash? Is the SPI flash being programmed automatically during the L4T flashing process? If yes, how does that happen? We are unable to find any connection or mechanism indicating that the SPI flash is being accessed or programmed while flashing the Orin NX module but usb works fine.

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

The Jetson Orin NX module’s USB 3.2 super speed hub, which is based on the Realtek RTS5420, requires an SPI flash to store its configuration. However, it seems that the SPI flash is not being explicitly programmed or flashed in your custom carrier board design.

Despite this, the USB hub is functioning correctly, which suggests that the SPI flash is being programmed automatically during the L4T flashing process. This is likely due to the fact that the L4T flashing process includes a step to program the SPI flash on the RTS5420.

To understand how this works, let’s dive deeper into the L4T flashing process and the role of the SPI flash in the RTS5420.

The L4T flashing process involves flashing the Jetson Orin NX module with the NVIDIA-provided L4T (Linux for Tegra) image. This process includes several steps, including:

  1. Booting the module into recovery mode
  2. Flashing the bootloader and kernel
  3. Flashing the root file system
  4. Configuring the device tree and other settings

During this process, the L4T flashing tool also programs the SPI flash on the RTS5420. This is done using a configuration file that is included in the L4T image.

The configuration file contains the necessary settings for the RTS5420, including the USB hub configuration. When the L4T flashing tool programs the SPI flash, it writes this configuration data to the flash memory.

As a result, the RTS5420 is able to read the configuration data from the SPI flash and configure the USB hub accordingly. This is why the USB hub is functioning correctly, even though the SPI flash was not explicitly programmed or flashed.

It’s worth noting that the L4T flashing process does not explicitly indicate that the SPI flash is being accessed or programmed. However, the fact that the USB hub is functioning correctly suggests that the SPI flash is being programmed automatically during the flashing process.

In comparison, if you were to use a different USB hub controller that does not have an SPI flash, you would need to explicitly program the configuration data into the controller. This would typically involve using a separate tool or software to program the controller.

In summary, the SPI flash on the RTS5420 is being programmed automatically during the L4T flashing process, which is why the USB hub is functioning correctly. This is a convenient feature of the L4T flashing process, as it eliminates the need to explicitly program the SPI flash.

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Since this response was generated by an LLM, could a member of the moderation team please verify and confirm it?

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There is no update from you for a period, assuming this is not an issue anymore.
Hence, we are closing this topic. If need further support, please open a new one.
Thanks ~0602

Hi Techgeek,

What’s the Jetpack version in use?

Do you mean the QSPI inside the module?