LSM6DSOX: 3 vs 4 wire SPI configuration

[ANist]

Hello, this should be a basic question but I am pretty new in this field. What are the core difference between a 3 and a 4 wir SPIe configuration for LSM6DSOX? Apart from electrical connection, is there any difference in Firmware design, capabilities etc ... ?

[Uwe Bonnes]

The 4th wire is chip select. De-asserting CS is a good way to abort a run-stray communication.

[ANist]

@Uwe Bonnes​  What do you mean by "aborting a run-stray communication" ?

[Uwe Bonnes]

"Run astray communication" in the sense that things do not happen as you expect it. With CS going high and the low again, the device starts from a known state in the SPI communication, like an SPI communication reset.