+char
+ao_usart_getchar(struct ao_stm_usart *usart)
+{
+ int c;
+ ao_arch_block_interrupts();
+ while ((c = _ao_usart_pollchar(usart)) == AO_READ_AGAIN)
+ ao_sleep(&usart->rx_fifo);
+ ao_arch_release_interrupts();
+ return (char) c;
+}
+
+static inline uint8_t
+_ao_usart_sleep_for(struct ao_stm_usart *usart, uint16_t timeout)
+{
+ return ao_sleep_for(&usart->rx_fifo, timeout);
+}
+