void
ao_i2c_init(void);
+/* ao_serial_stm.c */
+struct ao_stm_usart {
+ struct ao_fifo rx_fifo;
+ struct ao_fifo tx_fifo;
+ struct stm_usart *reg;
+ uint8_t tx_started;
+};
+
+#if HAS_SERIAL_1
+extern struct ao_stm_usart ao_stm_usart1;
+#endif
+
+#if HAS_SERIAL_2
+extern struct ao_stm_usart ao_stm_usart2;
+#endif
+
+#if HAS_SERIAL_3
+extern struct ao_stm_usart ao_stm_usart3;
+#endif
+
#define ARM_PUSH32(stack, val) (*(--(stack)) = (val))
static inline uint32_t