If a SLOTx is not active in Multi-LED mode then once the samples for the active slots have been taken, the FIFO will move on to the next sample. There are no dummy bytes generated. For example, with only RED and IR LEDs used. This means that both the RED and IR channels will each generate three bytes (2x3 bytes) in the order they are set in the SLOTx and then return to sample the first channel again.