HEART_CLR_ALL_MASK
heart_write(HEART_CLR_ALL_MASK, &heart_regs->imr[0]);
heart_write(HEART_CLR_ALL_MASK, &heart_regs->imr[1]);
heart_write(HEART_CLR_ALL_MASK, &heart_regs->imr[2]);
heart_write(HEART_CLR_ALL_MASK, &heart_regs->imr[3]);