makeflyeasy PixPilot-C3

../_images/PixPilot-C3.png

The PixPilot-C3 is a low cost flight controller with fully redundant IMUs. In most cases, an onboard compass is more susceptible to interference, so we removed the onboard compass and used an external compass instead. Integrated high gain buzzer. The PixPilot-C3 flight controller is sold by a range of resellers listed on the makeflyeasy(http://www.makeflyeasy.com)

Specifications

  • Processor:

    • 32-bit STM32F427VIT6 ARM Cortex M4 core with FPU

    • 168 Mhz/256 KB RAM/2 MB Flash

    • 32-bit failsafe co-processor (STMF103)

  • Sensors

    • TWO redundant IMUs (accels and gyros)

    • Gyro/Accelerometers: two ICM42688-P(SPI)

    • Barometers: Two redundant BMP388 barometers

  • Power

    • Redundant power supply with automatic failover

    • Power supply 4V-6V

  • Interfaces

    • 14x PWM servo outputs (8 from IO, 6 from FMU)

    • S.Bus servo output

    • R/C inputs for CPPM, Spektrum / DSM and S.Bus

    • 5x general-purpose serial ports

    • 2x I2C ports

    • 2x CAN Bus interface

    • MicroSD card reader

    • Type-C USB

    • High-powered piezo buzzer driver

    • Safety switch / LED

    • Servo rail BEC independent power input for servos

  • Dimensions

    • Weight 40g

    • Size 74mm x 45mm x 16mm

UART Mapping

  • SERIAL0 -> console (primary mavlink, usually USB)

  • SERIAL1 -> USART2 (telem1,DMA-enabled)

  • SERIAL2 -> USART3 (Telem2,DMA-enabled)

  • SERIAL3 -> UART4 (GPS1)

  • SERIAL4 -> UART8 (GPS2,DMA-enabled)

  • SERIAL5 -> UART7 (USER)

Pinouts

../_images/PixPilot-C3_Pinout.png

Connector pin assignments

TELEM1, TELEM2 ports

Pin Signal Volt
1 VCC +5V
2 TX (OUT) +3.3V
3 RX (IN) +3.3V
4 GND GND

I2C1, I2C2 ports

PIN SIGNAL VOLT
1 VCC +5V
2 SCL +3.3V
3 SDA +3.3V
4 GND GND

CAN1, CAN2 ports

PIN SIGNAL VOLT
1 VCC +5V
2 CAN_H +12V
3 CAN_L +12V
4 GND GND

Safety port

PIN SIGNAL VOLT
1 VCC +5V
2 LED +5V
3 SAFKEY +5V

GPS1/I2C1, GPS2/I2C2 ports

PIN SIGNAL VOLT
1 VCC +5V
2 TX +3.3V
3 RX +3.3V
4 SCL +3.3V
5 SDA +3.3V
6 GND GND

Serial5 port

Pin Signal Volt
1 VCC +5V
2 TX (OUT) +3.3V
3 RX (IN) +3.3V
4 GND GND

Power1, Power2 ports

PIN SIGNAL VOLT
1 VCC +5V
2 VCC +5V
3 CURRENT +3.3V
4 VOLTAGE +3.3V
5 GND GND
6 GND GND

DSM ports

PIN SIGNAL VOLT
1 VCC +3.3V
2 RX +3.3V
3 GND GND

RC Input

The SBus input pin, which by default is mapped to a timer input, can be used for all ArduPilot supported receiver protocols, except CRSF/ELRS and SRXL2 which require a true UART connection. However, FPort, when connected in this manner, will only provide RC without telemetry.

To allow CRSF and embedded telemetry available in Fport, CRSF, and SRXL2 receivers, a full UART, such as SERIAL4 (UART8) would need to be used for receiver connections. Below are setups using UART4. SERIAL4_PROTOCOL should be set to “23”.

Any UART can be used for RC system connections in ArduPilot also, and is compatible with all protocols except PPM. See Radio Control Systems for details.

PWM Output

The PixPilot-V3 supports up to 14 PWM outputs. First first 8 outputs (labelled S1 to S8) are controlled by a dedicated STM32F103 IO controller. These 8 outputs support all PWM output formats, but not DShot.

The remaining 6 outputs (labelled AUX1 to AUX6) are the “auxiliary” outputs. These are directly attached to the STM32F427 and support all PWM protocols as well as DShot.

All 14 PWM outputs have GND on the top row, 5V on the middle row and signal on the bottom row.

The 8 main PWM outputs are in 3 groups:

  • PWM 1 and 2 in group1

  • PWM 3 and 4 in group2

  • PWM 5, 6, 7 and 8 in group3

The 6 auxiliary PWM outputs are in 2 groups:

  • PWM 1, 2, 3 and 4 in group1

  • PWM 5 and 6 in group2

Channels within the same group need to use the same output rate. If any channel in a group uses DShot then all channels in the group need to use DShot.

Battery Monitor Settings

These should already be set by default. However, if lost or changed:

Enable Battery monitor with these parameter settings :

BATT_MONITOR =4

Then reboot.

BATT_VOLT_PIN 2

BATT_CURR_PIN 3

BATT_VOLT_MULT 18.0

BATT_AMP_PERVLT 24.0

BATT2_VOLT_PIN 14

BATT2_CURR_PIN 13

BATT2_VOLT_MULT 18.0

BATT2_AMP_PERVLT 24.0

DroneCAN capability

There are 2 CAN ports which allow connecting two independant CAN bus outputs. Each of these can have multiple CAN peripheral devices connected.

Loading Firmware

The board comes pre-installed with an ArduPilot compatible bootloader, allowing the loading of xxxxxx.apj firmware files with any ArduPilot compatible ground station.

Firmware for these boards can be found here in sub-folders labeled “PixPilot-C3”.

Where to Buy

makeflyeasy