IEVME_ATTEN
iev->status |= IEVME_ATTEN; /* flag! */
iev->status &= ~IEVME_ATTEN; /* down. */
write_iev(vsc, status, read_iev(vsc, status) | IEVME_ATTEN);
write_iev(vsc, status, read_iev(vsc, status) & ~IEVME_ATTEN);