How to detect devices on I2C_GP1, I2C_GP2, I2C_GP3?

Robotics & Edge Computing Jetson & Embedded Systems Jetson TX2
1

I am trying to detect multiple devices that are connected to my Jetson TX2 through a custom carrier board using I2C_GP1, I2C_GP2, and I2C_GP3. The TX2 Developer Kit Carrier Board Design Files were used as a guide for the custom carrier board. How can I scan and communicate with these devices on these I2C busses?
Thanks

2

Hi mmorsy,

You can use i2ctools for this task, the usage is really simple:

sudo i2cdetect -r -y <i2c-bus>

The output would be as follows:

nvidia@nvidia-desktop:~$ sudo i2cdetect -r -y 2
     0  1  2  3  4  5  6  7  8  9  a  b  c  d  e  f
00:          -- -- -- -- -- -- -- -- -- -- -- -- -- 
10: -- -- -- -- -- -- -- -- 18 -- -- -- -- -- -- -- 
20: -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- 
30: 30 UU UU UU UU -- -- -- -- -- -- -- -- -- -- -- 
40: -- UU UU UU UU 45 -- -- UU -- UU -- -- -- -- -- 
50: -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- 
60: -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- 
70: -- -- -- -- -- -- -- --

More info here: https://linux.die.net/man/8/i2cdetect

-Jafet

3

Thank you Jafet for your response.

Does correspond to the number associated with I2C_GP1, I2C_GP2, and I2C_GP3?
In your example of “sudo i2cdetect -r -y 2”, should this detect devices on the I2C_GP2_DAT / I2C_GP2_CLK lines?

Thanks

4

Hi mmorsy,

The I2C connections would be as shown below, it can be obtained from OEM Product Design Guide (Figure 40. I2C Connections): https://developer.nvidia.com/embedded/dlc/jetson-tx2-series-oem-product-design-guide

I2C numeration in device tree starts at 0 (https://developer.ridgerun.com/wiki/index.php?title=JetsonTX2/Getting_Started#I2C). Basically it is as follows:

  • I2C_GP0 -> = 1
  • I2C_GP1 -> = 0
  • I2C_GP2 -> = 6
  • I2C_GP3 -> = 8

Hope this info helps,

-Jafet

5

Thanks so much Jafet. I’ll try that.