Any ideas why i2c device doesn't show up on the first scan?

[/RaspberryPi]

I was having problems with i2c. I'm using two devices on the same bus. The other bus (0) shows all addresses, something's wrong with it.
Anyway when I run i2cdetect -y 1 the device (MPU9250) does not show up on the first scan, its address is default eg. 68. The other device on the same bus VL53L0X shows up as 28/runs fine.
On the second run, the device (68) shows up.
The other issue is when I try to run a sample against the IMU it fails to run for several calls (IO error)... I call i2cdetect -y 1 a few times thinking it will trigger it to work somehow.
Anyway eventually it works... and then it just runs. No IO error, I get my stream of data. It runs as long as I want.

submitted by /u/post_hazanko
[link] [comments]

More...