By default, SPI data transmission between a master and a slave looks like this.SS release between frames is disabled.
However, some slave devices require SS line to be released and deasserted between data frames.SS release between frames is enabled.
In this case an SS line is released after each frame and asserted before the next frame. If delay between frames is specified, the SS line will be released for the whole delay duration. Yet, the line will still be released and asserted between data frames even if this delay is zero.