Trouble sending i2c from TX2 to slave

Robotics & Edge Computing Jetson & Embedded Systems Jetson TX2
1

I have a computer science background and a little embedded systems programming with an ST MicroElectronics STM32 board, but I am new to the Jetson TX2 board and i2c communication with Linux. I am trying to send i2c information from the tx2 to the Adafruit 16 - channel servo controller, but am getting Remote I/O errors.
Here is my code:

code
code1610×976 148 KB

My terminal output:
terminal
terminal734×462 39.7 KB

My output when I search i2cdetect:
i2cDetect
i2cDetect734×462 98.3 KB

I am also connected to the bus with sdl and sca pins on the j21 pinout here:
pinout
pinout717×554 132 KB

I have been following the Linux Wiki for interacting with i2c devices, but have had no luck. I open the file descriptor and then use ioctl with the i2c address of 0x40. However, when I try to write to the i2c, I get a Remote I/O error. I noticed there is also something at address 0x70. In the Linux wiki it mentions, under the Writing to ADC section that some devices require you to write to a device register. Is that what I am missing? Please help. I have been working on this for a little while now and would like to learn and push my project forward. Thank you in advance.

Charlie Barber

4

Can you make sure the Adafruit device is powered up correctly? If other devices on this bus can be detected, then it should be your device problem.

6

It was powered up. The problem I found was that I was not sending the register to write to along with the data in the write call. Thank you for the response

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