33.6.3.7 Host Inter-Character Spacing
When configured as the host, inter-character spacing can be increased by writing a non-zero value to the Inter-Character Spacing bit field in the Control C register (CTRLC.ICSPACE). When non-zero, CTRLC.ICSPACE represents the minimum number of baud cycles that the SCK clock line does not toggle and the next character is stalled.
The following figure illustrates an example for CTRLC.ICSPACE = 4; in this case, the SCK is inactive for four baud cycles.