UARTSR1_RDRF
if (sts & UARTSR1_RDRF && !sport->lpuart_dma_rx_use)
if (readb(sport->port.membase + UARTSR1) & UARTSR1_RDRF) {
if (readb(port->membase + UARTSR1) & UARTSR1_RDRF) {
if (!(readb(port->membase + UARTSR1) & UARTSR1_RDRF))