IB_TIMC
MFP->mf_ierb &= ~IB_TIMC; /* Disable timer inter. */
MFP->mf_iprb = (u_int8_t)~IB_TIMC;/* Clear pending interrupts */
MFP->mf_ierb |= IB_TIMC; /* Enable timer interrupts */
MFP->mf_imrb |= IB_TIMC; /* ..... */