AUAV-X2 USER MANUAL 2014

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SPECIAL THANKS to PHILLIP KOCMOUD, MARK WHITEHORN and LORENZ MEIER

A/ AUAV-X2 basic views
AUAV-X2 USER MANUAL 2014

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FRONT HEADERS

REAR HEADERS
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SIDE HEADERS
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SAFETY BUTTON CONNECTIONS

1. FRONT HEADERS

a/ ADDITIONAL CHANNELS 

CH1 to CH5 are additional FMU channels, which could be used for anything, but for using 

them, the user should add his own code to the firmware. These additional channels could be 

used for PWM inputs, general purpose inputs or outputs, or analog inputs.

AIR, +5V and GND are the airspeed sensor pin set, where AIR is the analog input from the 

airspeed sensor, +5V and GND are used for powering an analogue airspeed sensor.

b/ CAN INTERFACE

GND, CANL, CANH and +5V are pins for interfacing CAN bus.
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c/ USART7 ( SERIAL5 )

GND, +5V, U7Rx and U7Tx are pins for interfacing the SERIAL5, used by default as FTDI 

console interface.

d/ USART3 ( SERIAL2 )

GND, +5V, U3Rx and U3Tx are pins for interfacing the SERIAL2, a general purpose serial 

interface.

e/ USART4( SERIAL3 )

U4Tx, U4Rx, +5V and GND are pins for interfacing the SERIAL3, used by default as GPS 

interface.

f/ ANALOG CHANNELS – ADC1 and ADC2

GND, +5V, ADC1 and ADC2 are pins for interfacing the analog inputs. 

NOTE! The full ADC voltage span should be within 3.3VDC.

If you need to measure higher voltages, please calculate a R-R divider !

g/ I2C1 INTERFACE

I2SCL, I2SDA, +5V and GND are pins for interfacing the I2C1 interface.

NOTE! Both SCL and SDA have internal 2k2 pullups to +5V.

h/ SBUS / PPM INTERFACE

GND, +5V, SORI ( SBUS OUT / RSSI IN ) and SIPI ( SBUS IN / PPM IN ) are pins for 

SBUS or PPM interfaces. The SIPI input has protection in case of back EMF from receiver 

in case it has additional servos connected to and powered from additional ESC. 

NOTE! If you need to connect additional servos/ESCs to the receiver and to 

avoid back EMF from it, you should use one of the following connection 

approaches:
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 Additional servos connected to the receiver:

a/ disconnect the +5V power from X2 to the receiver-use just SIGNAL and GND;

b/ power the receiver from additional 5V source ( ESC ).

 Additional ESCs connected to the receiver – you have 2 options:

a/ disconnect all ESC +5V RED cables from the receiver and power the receiver 

from the autopilot as by default. Use just SIGNAL and GND from ESCs;

b/ disconnect the +5V from the autopilot, and power the receiver from JUST 

ONE of the ESCs. Disconnect all other ESC +5V RED cables from the receiver.

2. REAR HEADERS

a/ SERVO HEADERS

S1 to S8 are the signal pins, +VS ( +VSERVO ) is the servo power supply rail, and GND is 

the GND rail.

NOTE! Please use just one ESC/BEC for powering the servo rail with 

voltage between 4.5VDC and 10VDC ! Also don’t forget that the servo bus 

operates at 50Hz for fixed wing and 400Hz in multirotors!

b/ POWER BRICK

GND, +5VBR, VOLT, CURR are respectively GND, Vcc BRICK , voltage sensing and 

current sensing.

NOTE! VCC BRICK could be between 4.5VDC and 10VDC !

Voltages from VOLTAGE and CURRENT sensing should be 3.3VDC max!

c/ BUZZER CONNECTOR

BUZ+ and BUZ- are pins for connecting the buzzer.
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NOTE! Please connect the buzzer supplied with + and – and colors as of 

the picture!

d/ SPEKTRUM CONNECTOR

U1Rx, GND and +3V3 SP are respectively SIGNAL ( YELLOW or GRAY ), GND

(BLACK) and power supply for SPEKTRUM receiver/satellite ( RED ).

e/ SAFETY BUTTON CONNECTOR

+3V3, LEDS and SF are respectively the safety button 3.3V power supply, LED signal and 

button contacts.

NOTE! Please connect the supplied button with the connector colors as of 

the rear headers picture! The safety button female cable colors must 

correspond to the picture colors!

3. SIDE HEADERS

a/ USART2 ( SERIAL1 ) HEADER

USART2 ( SERIAL1 ) is a full set serial interface :

Pin1 = GND

Pin2 = +5VP ( +5VDC from power supply for peripherals )

Pin3 = U2CTS

Pin4 = U2RTS

Pin5 = U2Tx

Pin6 = U2Rx

The header for USART2 ( SERIAL1 ) is not soldered, but supplied in the AUAV-X2

package. This serial interface could be used for telemetry.
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b/ EXTERNAL SPI INTERFACE

Pin1 = GND

Pin2 = +5VP ( +5VDC from power supply for peripherals )

Pin3 = SCK ( SPI clock )

Pin4 = SS ( Slave Select )

Pin5 = MISO ( Master In Slave Out )

Pin6 = MOSI ( Master Out Slave In )

4. JTAGs

There are two JTAG interfaces – FMU one over the FMU side and IO over the IO side. Both 

use the same leading holes and are designed to work with TC2030 Tag connector 

(http://www.tag-connect.com/TC2030-IDC-NL ).

Very useful device for debugging is the Black Sphere Debugger (http://www.tagconnect.com/BLACK-SPHERE-DBG ).

For flashing the bootloaders, firmware and debugging, the cheap STM32 Nucleo board could

also be used (http://mbed.org/platforms/?tvend=10 ).

The AUAV-X2 boards are supplied with both FMU and IO bootloaders flashed, so one 

doesn’t need to flash them again.

5. LEDS and SAFETY SWITCH

There are 4 LEDs on the X2 board – FMU status LED ( RED ), IO status LED ( RED ), 

Power LED ( GREEN ) and the GPS / Position LED ( BLUE ).

LED STATUS TABLE

GREEN = Power LED = always ON

BLUE = GPS / Position LED

OFF = No position sensor / GPS module found / Connected

SLOW BLINK = GPS or OPTICAL FLOW module found

FAST BLINK = Error
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SOLID = Position lock ( GPS or another sensor )

FMU RED LED ( ARMING LED )

SLOW BLINK = Ready to arm ( System self tests are OK )

FAST BLINK = Refusing to arm ( System self tests are NOT OK )

SOLID = Armed

IO RED ( FAILSAFE LED )

FAST BLINK = Bootloader active ( the BLUE LED should be off in this state )

4Hz = No FMU input

ON = Initialization error, check your RC config options in your parameters

OFF = System is OK

SAFETY SWITCH STATUS

ON = FMU and IO are ARMED

SLOW BLINK = Ready to arm

FAST BLINK = Error / Refusing to arm

LONG OFF with FAST DOUBLE BLINK = IO armed, but FMU not

LONG OFF with FAST QUAD BLINK = FMU armed, but IO not
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6. POWERING AUAV- X1

There are three power inputs – USB ( only for programming and testing ), Power from the 

Power Brick and Servo Power Bus. Here is the schematics of the power stage:

As seen from the schematics, the servo power bus is separated from the Brick Power and 

from the USB, by very low Vf Schottky diodes. PMEG2020CP has very low Vf...just a few 

hundred millivolts.

NOTE! The Power Brick voltage and the Servo Bus voltage must be 

between 4.5VDC and 10VDC ! The BEST temperature and EMI

performance from the DC-DC Buck-Boost Converter could be obtained 

with 5.5 to 6VDC from Power Brick and from 6VDC to 8VDC from Servo 

Bus. Thus, the DC-DC Buck-Boost works in Buck mode.

NOTE! The MicroSD card socket acts also as a heatsink for DC-DC BuckBoost regulator. It doesn’t dissipate much heat, BUT never cover it with 

heat insulating materials. Also DO NOT cover any of the other heat 

dissipating components ( LDO regulators and the STM32F4 processor )!
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VERY IMPORTANT NOTE! THE MAX ALLOWABLE TOTAL 

CURRENT CONSUMPTION FOR ALL PERIPHERALS IS 500 mA!

ALWAYS ALLOW AIR CIRCULATION OVER BOTH AUAV-X2

SURFACES!

7. UPLOADING THE FIRMWARE

a/ DOWNLOAD and INSTALL QGroundControl from :

http://qgroundcontrol.org/downloads

Install an empty FAT16 or FAT32 formatted MicroSD card into the AUAV – X2 MicroSD 

card socket. Connect the AUAV – X2 to the PC via USB-MicroUSB cable. 

In QGroundControl, click in the top left on CONFIG, then on the big green SCAN button.

After the board has been found, click on the FLASH / UPGRADE button to upgrade the 

firmware. 

Disconnect the USB cable from the PC, hold the safety switch pressed while powering on 

the system. Release the button. The IO RED boot LED will flash rapidly. The AUAV – X2

will boot normally. It will automatically upgrade the backup processor firmware.

A quick tutorial video can be found here. 

b/ AIRFRAME CONFIGURATION

Choose the Airframe Configuration from CONFIG menu. Choose your configuration and 

hit Apply and Restart button. The autopilot will restart.

c/ SENSOR CALIBRATION

Choose Sensor Calibration. Place the autopilot on a flat surface and don’t move it. Start with 

Gyro and Mag Calibration. For Accelerometer Calibration you need 3 perpendicular 

surfaces. You may use a cardboard box for. Use 3 of it’s surfaces to place the autopilot 

steady. Follow the plane positioning guide. First place the board, hold and wait till the 

system beeps. 

d/ RADIO CALIBRATION

Choose Radio Calibration from CONFIG menu. Follow the Radio Calibration procedure.
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e/ TEST MANUAL MODE

First step to get ready for flight is to test manual ( pass-through ) mode. This is where you 

control the aircraft directly from your R/C transmitter.

While the system will enter the manual mode state when powered only by USB, it will NOT 

be able to drive the servos. You must connect a battery or a BEC ( as described above ) for 

the flight modes to function properly. 

To test, you can just connect the BEC output ( throttle connector ) from your ESC or some 

other sufficient 5V source to the servo bus.

f/ MANUAL MODE

Make sure you have completed airframe settings and calibrations first ( radio and sensors ).

Enter manual mode as follows:

 Start QGroundControl ( optional )

 Turn on your R/C transmitter

 Connect the battery/BEC power source

 Connect the USB to your computer ( optional )

 Hold down the safety switch ( it should be doing a double blink )

 Hold transmitter stick at Throttle minimum ( down ) and YAW/Rudder full right

 You should hear the audio alarm for ARMED and the safety switch is solid green

 You should now be able to move the sticks/levers and see the servo move

 If you are having trouble, re-do the R/C calibration in QGroundControl

g/ TELEMETRY on AUAV-X2

First you need to prepare the cable. To prepare the cable, you just need a crimp pliers to 

crimp the pins supplied to the cables. You have to choose color #24-26 AWG cables. The 

colors you need are – BLACK for GND, RED for +5V, YELLOW for RTS, GREEN for 

TxD, ORANGE for RxD and BLUE for CTS for example, but you could use other colors 

for.

NOTE! THE TELEMETRY IS ON UART2 !

More on how to connect the telemetry you could read here .
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8. MICRO IMU V2 PINOUTS

9. SOME VERY GOOD REFERENCES 

AUAX-X1 GITHUB - https://github.com/pkocmoud

PX4/PIXHAWK - http://pixhawk.org/

ARDUPILOT - http://ardupilot.com/