UCR1_RXDMAEN
ucr1 |= UCR1_RXDMAEN | UCR1_TXDMAEN | UCR1_ATDMAEN;
ucr1 &= ~(UCR1_RXDMAEN | UCR1_TXDMAEN | UCR1_ATDMAEN);
ucr1 &= ~(UCR1_TRDYEN | UCR1_RRDYEN | UCR1_RTSDEN | UCR1_RXDMAEN |
ucr1 |= UCR1_RXDMAEN | UCR1_ATDMAEN;
ucr1 &= ~(UCR1_RXDMAEN | UCR1_ATDMAEN);