On 22.12.2021 14.32, Mark Brown wrote: > On Wed, Dec 22, 2021 at 07:59:57AM +0200, Oskari Lemmela wrote: >> If bits_per_word is configured, transfer only word amount >> of data per iteration. > Does this actually materially affect what the hardware does? How much > data is transferred in an internal loop in the driver is completely > immaterial, bits per word only matters for formatting of the transferred > data. I don't have logic analyzator to verify what hardware actual does. I tested this with transferring 32bits to ATSAMD20J15 slave. Running loop in 8bits or 16bits, transfer is done correctly without any errors. When running loop in 24bits or 32bits directly I got error from spi_sync_transfer. Oskari