Does the Jetson Nano perform an ID-EEPROM Query on Boot

The GPIO header on the Jetson Nano has essentially the same Pinout as the Raspberry Pi. However, I cannot find any documentation on the I2C bus that is on Pins 27 and 28.

On the Raspberry Pi, these pins are queried during boot to check if any external accessories have an EEPROM chip on board. According to the official Raspberry Pi Specification, these pins are not to be used for anything besides ID EEPROM.

Does the Jetson Nano query these pins on boot like the Raspberry Pi, or are they just a normal I2C bus?

hello lockheedmaniac,

there’re board information for device recognition,
you may also check developer guide for reference, Jetson Module EEPROM Layout.


That does not answer my question. I am not talking about the EEPROM on the development board, but the I2C Bus on pins 28 and 29 of the GPIO header. The Jetson Nano copies the Raspberry Pi Pinout.
On the Raspberry Pi, these two pins (and the I2C bus that they are attached to) are reserved to be used for identification of expansion boards and configuration of the device tree to support said expansion boards.

I am looking to determine if the Jetson Nano performs this same pattern of querying a specific I2C address on startup to check if expansion boards are attached, and if so, how to take advantage of this.

hello lockheedmaniac,

please check NVIDIA Jetson Nano J41 Header Pinout, you may also refer to spreadsheet map to RPi to help.

@JerryChang I know about the Pinout. I am talking about on the software side. Does L4T Query pins 28 and 29 to determine if there are expansion boards attached, like in the HAT Specification I linked in the original post.

hello BarrowWight,

please use kernel APIs for checking them,
for example,
pin-28 / I2C_1_SCL, please check with I2C driver calls.
pin-29 / CAM_AF_EN, you may check for GPIO,