The [CBUnmanned H743 Stamp](https://cbunmanned.com/store) is a flight controller loosely based on the FMUv6 standards & is designed for low volume OEMs as a drop in way to add ArduPilot to their custom hardware builds. It is a part of CBUnmanned's wider ["Stamp" Eco-System](https://cbunmanned.com), which brings together all the typical avionics hardware into a neat custom carrier PCB. Mounting footprints and symbols are available along with examples of basic usage on the [Wiki](https://wiki.cbunmanned.com/).
Serial 2, 5 & 7 have RTS/CTS pins, the other UARTs do not have RTS/CTS.
GPS 1 & 2 are on Serial 3 & 4 respectively.
### RC Input
RC input is configured on the USART 6 Rx Pin. This pin allows all RC protocols compatible with direct connection to a H7 IC (SBus requires setting the bitmask for hardware inversion, CRSF etc), PPM is NOT supported.
USART 6 Tx is available for use with bi directional protocols.
An optional IOMCU can be connected to this serial port, a compatible custom build of the firmware required.
The Stamp supports up to 10 PWM outputs with D-Shot.
The PWM outputs are in 3 groups:
- PWM 1 - 4 in group 1 (Timer 5)
- PWM 5 - 8 in group 2 (Timer 4)
- PWM 9 & 10 in group 3 (Timer 2)
Channels within the same group need to use the same output rate. If any channel in a group uses D-Shot then all channels in the group need to use D-Shot.
BiDirectional DShot available on the first 8 outputs.
Ethernet is available on 4 output pads and has internal magnetics supporting direct connection to external equipment, no need for a large RJ45 connector.
### Compass
The H743 Stamp has a built in compass, the BMM150. Due to potential interference the board is usually used with an external I2C or CAN compass as part of a GPS/Compass combination.
### USB
USB Signals D+ & D- are available to route to a suitable connector for your project.
### Safety Button
Optional, if it is not fitted remove the check from arming mask. To activate short this pad to 3.3v with a momentary push button (Press & Hold).
### Power
A regulated 3.3v output is available from the stamp for use with the safety button. WARNING! This is shared with the main IC - Do NOT use for accessories. Keep current draw under 0.1A!
The Stamp requires a stable 5v supply input of at least 1.5A. This directly powers the 5v components and supplies the 3.3v LDOs with power. Typical idle usage is 0.35A @ 5v.
## Loading Firmware
The board comes pre-installed with an ArduPilot compatible bootloader, allowing the loading of *.apj firmware files with any ArduPilot compatible ground station.
Firmware Taget = CBU-H7-Stamp
A built in button can be used to activate DFU Mode by being pressed during power up. The DFU Activate pin is broken out to allow remote mounting of this button if required.
