AHC_PRIMARY_CHANNEL
slave->flags &= ~AHC_PRIMARY_CHANNEL;
master->flags & AHC_PRIMARY_CHANNEL;
(ahc->flags & AHC_PRIMARY_CHANNEL) + 'A');
&& (ahc->flags & AHC_PRIMARY_CHANNEL) != 0) {
&& (ahc->flags & AHC_PRIMARY_CHANNEL) != 0) {