12.1.5.3.3.5.1 Programming Tips When Switching to Another Channel
When a single channel is enabled and data transfer is ongoing:
Wait for the MCSPI word transfer to complete
(wait until the MCSPI_CHSTAT_0/1/2/3[2] EOT bit is set to 1) before disabling
the current channel and enabling a different channel.
Disable the current channel, and then enable the other channel.