Support different I2C addresses

[pkb-pmj]

MPU9250 can have one of two I2C addresses: 0x68 or 0x69. That way you can use two MPUs on one I2C bus.
As far as I know, SPI doesn't have anything similar.
Is it possible to add this feature, given that the crate is built around SPI?

[little-arhat]

This crate uses Device trait, and there are implementation of this for SPI & I2C. I2C Addr is hardcoded atm, but it's possible to make it configurable.

Feel free to add a PR (otherwise I'll take a look over the weekend).

[bofh]

Chip select signal is used to select device on SPI bus, so you need to have an output pin per sensor to choose to which to talk to.

[bofh]

But you right, we need to add AD0 support in I2C mode.

[little-arhat]

Also, fyi, it's possible to share one i2c bus using smth like shared_bus: example.

[pkb-pmj]

I've just realized, it would have been hard if MPU9250 was also a trait, but since it's a struct impl, it can be different for I2C and SPI... and even already is.
So it's just a matter of adding address to I2cDevice and replacing i2c with i2c, address in all the "constructors", just like the existing spi, ncs.
I'll add a PR today.

[pkb-pmj]

Side note: I've never had a reason to read how nCS works, but that makes sense. You could also use AD0 in the same way xD
I would totally do that, but with 3 sensors on one bus it would require 5 pins, while two buses require 4.

shared_bus looks like it solves a different problem, which in Arduino/C++ doesn't even exist, you just pass Wire as an argument and don't worry about ownership as long as it does what it's supposed to.