# Onboard FMU on Airvolute DCS2.Pilot board
DroneCore 2.0 is a modular AI-driven open architecture autopilot designed for complex use cases that combines high computational processing power, redundant connectivity, small size, and low weight.The autopilot represents a one-stop-solution for developers integrating the functionality of carrier board, companion computer, and power distribution board into a single compact form factor.
This system usually uses a "CUBE" autopilot as its primary FMU, but can use an onboard STM32H743 as the FMU. This board definition and firmware on `the ArduPilot firmware server <https://firmware.ardupilot.org>`__ is for this secondary FMU
For more informations on DCS2.Pilot board see:
https://docs.airvolute.com/dronecore-autopilot/dcs2
## Where To Buy
info@airvolute.com
## Features
- MCU: STM32H743
- IMU: BMI088
- Barometer: BMP390
- 2 UARTS
- 2 CAN buses
- 4 PWM outputs
- PPM (RC input)
- external SPI and I2C
- SD card connector
- USB connection onboard with Jetson Host
- Ethernet
## DCS2.Pilot peripherals diagram
<img width="957" alt="DC2 Pilot peripherals" src="https://github.com/vrsanskytom/ardupilot/blob/hwdef_for_airvolute_dcs2/libraries/AP_HAL_ChibiOS/hwdef/Airvolute-DCS2/DC2.Pilot%20peripherals.png">
## DCS2.Pilot onboard FMU related connectors pinout
### Top side
<img width="818" alt="DCS2 Pilot_bottom" src="https://github.com/vrsanskytom/ardupilot/blob/hwdef_for_airvolute_dcs2/libraries/AP_HAL_ChibiOS/hwdef/Airvolute-DCS2/DCS2.Pilot_TopSide.png">
#### <ins>PPM connector (RC input)</ins>
JST GH 1.25mm pitch, 3-Pin
Matching connector JST GHR-03V-S.
RC input is configured on the PPM_SBUS_PROT pin as part of the PPM connector. Pin is connected to UART3_RX and also to analog input on TIM3_CH1. This pin supports all unidirectional RC protocols, but for it to be enabled, it is necessary to set SERIAL3_PROTOCOL as RCIN. Also RC input is shared with primary FMU, so it is default disabled on this secondary FMU.
5V supply is limited to 1A by internal current limiter.
<table border="1" class="docutils">
<tbody>
<tr>
<th>Pin </th>
<th>Signal </th>
</tr>
<tr>
<td>1</td>
<td>GND</td>
</tr>
<td>2</td>
<td>5V</td>
</tr>
<td>3</td>
<td>PPM</td>
</tr>
</tbody>
</table>
### Bottom side
<img width="811" alt="DCS2 Pilot_top" src="https://github.com/vrsanskytom/ardupilot/blob/hwdef_for_airvolute_dcs2/libraries/AP_HAL_ChibiOS/hwdef/Airvolute-DCS2/DCS2.Pilot_BottomSide.png">
#### <ins>FMU SEC. connector</ins>
JST GH 1.25mm pitch, 12-Pin
Matching connector JST GHR-12V-S.
The DCS2 Onboard FMU supports up to 4 PWM outputs. These are directly attached to the STM32H743 and support all PWM protocols as well as DShot and bi-directional DShot.
The 4 PWM outputs are in 2 groups:
PWM 1,2 in group1
PWM 3,4 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.
5V supply is limited to 1A by internal current limiter.
<table border="1" class="docutils">
<tbody>
<tr>
<th>Pin </th>
<th>Signal </th>
</tr>
<tr>
<td>1</td>
<td>GND</td>
</tr>
<td>2</td>
<td>GND</td>
</tr>
<td>3</td>
<td>GPIO/PWM output 4</td>
</tr>
</tr>
<td>4</td>
<td>GPIO/PWM output 3</td>
</tr>
</tr>
<td>5</td>
<td>GPIO/PWM output 2</td>
</tr>
</tr>
<td>6</td>
<td>GPIO/PWM output 1</td>
</tr>
</tr>
<td>7</td>
<td>Serial 1 RX</td>
</tr>
</tr>
<td>8</td>
<td>Serial 1 TX</td>
</tr>
</tr>
<td>9</td>
<td>Serial 2 RX</td>
</tr>
</tr>
<td>10</td>
<td>Serial 2 TX</td>
</tr>
</tr>
<td>11</td>
<td>5V</td>
</tr>
</tr>
<td>12</td>
<td>5V</td>
</tr>
</tbody>
</table>
#### <ins>EXT. SENS. connector</ins>
BM23PF0.8-10DS-0.35V connector
Matching connector BM23PF0.8-10DP-0.35V
This connector allows connecting external IMU with I2C and SPI data buses.
5V supply is limited to 1.9A by internal current limiter.
<table border="1" class="docutils">
<tbody>
<tr>
<th>Pin </th>
<th>Signal </th>
</tr>
<tr>
<td>1</td>
<td>SPI_MOSI</td>
</tr>
<td>2</td>
<td>SPI_MISO</td>
</tr>
<td>3</td>
<td>SPI_SCK</td>
</tr>
</tr>
<td>4</td>
<td>SPI_CS0</td>
</tr>
</tr>
<td>5</td>
<td>SPI_CS1</td>
</tr>
</tr>
<td>6</td>
<td>SPI_CS2</td>
</tr>
</tr>
<td>7</td>
<td>SPI_CS3</td>
</tr>
</tr>
<td>8</td>
<td>IMU_DRDY_EXT</td>
</tr>
</tr>
<td>9</td>
<td>I2C_SE_SDA</td>
</tr>
</tr>
<td>10</td>
<td>I2C_SE_SCL</td>
</tr>
</tr>
<td>MP1</td>
<td>5V</td>
</tr>
</tr>
<td>MP2</td>
<td>5V</td>
</tr>
</tr>
<td>MP3</td>
<td>GND</td>
</tr>
</tr>
<td>MP4</td>
<td>GND</td>
</tr>
</tbody>
</table>
#### <ins>ETH EXP. connector</ins>
505110-1692 connector
Ethernet connector is routed to FMU through onboard switch.
The onboard FMU is connected via the RMII bus with a speed of 100 Mbits.
#### <ins>SD card connector</ins>
MEM2085-00-115-00-A connector
Connector for standard microSD memory card. This card is primarily used to store flight data and logs.
## Other connectors
### CAN 1, CAN 2 connectors
The board contains two CAN buses - CAN1 and CAN 2. The buses support speeds up to 1 Mbits and in FD mode up to 8 Mbits.
These connectors are not part of DCS2.Pilot board, but they are routed on DCS2.Adapter_board. This board (DCS2.Adapter_board) is fully modular and can be modified according to the customer's requirements. For more informations see: https://docs.airvolute.com/dronecore-autopilot/dcs2/adapter-extension-boards/dcs2.-adapter-default-v1.0/connectors-and-pinouts
JST GH 1.25mm pitch, 4-Pin
Matching connector JST GHR-04V-S.
5V supply is limited to 1.9A by internal current limiter.
<table border="1" class="docutils">
<tbody>
<tr>
<th>Pin </th>
<th>Signal </th>
</tr>
<tr>
<td>1</td>
<td>5V</td>
</tr>
<td>2</td>
<td>CAN_H</td>
</tr>
<td>3</td>
<td>CAN_L</td>
</tr>
<td>4</td>
<td>GND</td>
</tr>
</tbody>
</table>
## UART Mapping
- SERIAL0 -> USB (Default baud: 115200)
- SERIAL1 -> UART1 (FMU SEC) (Default baud: 57600, Default protocol: Mavlink2 (2))
- SERIAL2 -> UART2 (FMU SEC) (Default baud: 57600, Default protocol: Mavlink2 (2))
- SERIAL3 -> UART3 (RX pin only labeled as PPM on PPM connector) (Since this is a secondary FMU, default protocol is set to NONE instead of RCIN (23))
UARTs do not have RTS/CTS. UARTs 1 and 2 are routed to FMU_SEC. connector.
## Loading Firmware
Initial bootloader load is achievable only by SDW interface. Then it is possible to flash firmware thrugh onboard USB connection with Jetson host.