diff --git a/conf/airframes/flyingtux.xml b/conf/airframes/flyingtux.xml
index e61e87a012..6d41ace772 100644
--- a/conf/airframes/flyingtux.xml
+++ b/conf/airframes/flyingtux.xml
@@ -124,6 +124,9 @@ fbw.srcs += radio_control.c $(SRC_ARCH)/ppm_hw.c
 fbw.CFLAGS += -DDOWNLINK -DUART0 
 fbw.srcs += fbw_downlink.c $(SRC_ARCH)/uart_hw.c
 
+fbw.CFLAGS += -DINTER_MCU -DMCU_SPI_LINK
+fbw.srcs += inter_mcu.c $(SRC_ARCH)/spi_hw.c
+
 ap.CFLAGS += -DDOWNLINK -DUSE_UART0 
 ap.srcs += downlink.c $(SRC_ARCH)/uart_hw.c
 
diff --git a/sw/airborne/avr/spi_hw.h b/sw/airborne/avr/spi_hw.h
new file mode 100644
index 0000000000..8ea0dd023c
--- /dev/null
+++ b/sw/airborne/avr/spi_hw.h
@@ -0,0 +1,76 @@
+#ifndef SPI_HW_H
+#define SPI_HW_H
+
+#ifdef FBW
+
+#define SPI_PORT   PORTB
+#define SPI_PIN    PINB
+#define SPI_SS_PIN 2
+
+#define SpiIsSelected() (bit_is_clear(SPI_PIN, SPI_SS_PIN))
+
+#endif /* FBW */
+
+#ifdef AP
+
+#define SPI_SS0_PIN  0
+#define SPI_SS0_PORT PORTB
+#define SPI_SS0_DDR  DDRB
+#define SPI_IT0_PIN  1
+#define SPI_IT0_PORT PORTD
+#define SPI_IT0_DDR  DDRD
+
+#define SPI_SS1_PIN  7
+#define SPI_SS1_PORT PORTE
+#define SPI_SS1_DDR  DDRE
+#define SPI_IT1_PIN  6
+#define SPI_IT1_PORT PORTE
+#define SPI_IT1_DDR  DDRE 
+
+#define SPI_SCK_PIN  1
+#define SPI_MOSI_PIN 2
+#define SPI_MISO_PIN 3
+#define SPI_PORT PORTB
+#define SPI_DDR  DDRB
+
+#define SPI_START(_SPCR_VAL) { \
+  uint8_t foo; \
+  SPCR = _SPCR_VAL; \
+  if (bit_is_set(SPSR, SPIF)) \
+    foo = SPDR; \
+  SPCR |= _BV(SPIE); \
+}
+
+#define SPI_SELECT_SLAVE0() { \
+  spi_cur_slave = SPI_SLAVE0; \
+  cbi( SPI_SS0_PORT, SPI_SS0_PIN );\
+}
+
+#define SPI_UNSELECT_SLAVE0() { \
+  spi_cur_slave = SPI_NONE; \
+  sbi( SPI_SS0_PORT, SPI_SS0_PIN );\
+}
+
+#define SPI_SELECT_SLAVE1() { \
+  spi_cur_slave = SPI_SLAVE1; \
+  cbi( SPI_SS1_PORT, SPI_SS1_PIN );\
+}
+
+#define SPI_UNSELECT_SLAVE1() { \
+  spi_cur_slave = SPI_NONE; \
+  sbi( SPI_SS1_PORT, SPI_SS1_PIN );\
+}
+
+#define SPI_SEND(data) { \
+  SPDR = data; \
+}
+
+#define SPI_STOP() { \
+ cbi(SPCR,SPIE); \
+ cbi(SPCR, SPE); \
+}
+
+#endif /* AP */
+
+
+#endif /* SPI_HW_H */