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OpenVTx aims to provide firmware with MSP, SmartAudio and Tramp protocols. Any protocol can be used on the flight controller and on VTx power up the protocol used is automatically detected by OpenVTx.
From OpenVTx 0.2 and Betaflight 4.4 MSP will be the preferred protocol to use.
Currently SA is fully implemented and test against Rev. 09. To date IMRC has not released a protocol standard and implementation is based on information found within Betaflight.
MSP Control - MSP is the most common and vender neutral communication protocol. Like SmartAudio and TRAMP it can be used to set the VTx frequency, power, and pitmode. It has the added benefit of being able to self configure the VTx Table used in Betaflight. When the VTx powers up it will query the flight controller and check for a VTx Table. If it does not exist, or is incorrect, then OpenVTx will send the correct VTx Table to the flight controller.
Race Mode - When at a race event and using pitmode on a switch with Betaflight, select the RCE VTx power level. It will force pitmode on boot and only use 25mW.
The Red LED will power on at boot and twinkle when saving changes. Green and Blue indicate current operating mode (band/channel/power) when using MSP, SmartAudio, or the VTx Button. Not supported with TRAMP due to TRAMP not having a fixed VTx Table.
The VTX mode LED indication logic:
When using TRAMP or LED_INDICATION_OF_VTX_MODE=0, Red LED will power on at boot and twinkle when saving changes. Green will turn on when a protocol has been detected e.g. successful communication via TRAMP with the flight controller. Blue will blink every time a communication packet is received.
If OpenVTx detects an error the Red LED will flash one of the error codes below.
- RTC6705 not detected - 1s on to indicate start of the error code, followed by 3 quick flashes.
From Betaflight 4.4 MSP will be the preferred protocol to use. Connect the single VTx telemetry wire as normal to a FC uart Tx pad. Then select that uart from the OpenVTx Preset. There is no need to configure the Ports tab for the VTx, as the Preset will handle the Port setup for you. On power up the VTx will then check and configure the VTx Table.
If using SmartAudio or TRAMP, setup the Ports tab as normal, then pick the SmartAudio/TRAMP option from the OpenVTx Preset.
The online Configurator can be used with Chrome https://openvtx.org/.
Any VTx that is currently connected to a flight controller and working via MSP/SA/TRAMP can be updated. For newly flashed DIY hardware with just the bootloader flashed, the FC must be setup with SA as that is the default protocol for the bootloader.
- First close any flight controller Configurators. If open they will connect to the FC and block the update.
- Power the FC and VTx.
- Connect the FC USB.
- Select the Version, Target, and press Flash.
OpenVTx is continually adding support for more hardware. The most up to date list will be found in the platformio.ini file. https://github.com/OpenVTx/OpenVTx/blob/master/src/platformio.ini
fubarphill has made a fairly thorough video explaining the project and flashing process on youtube. Please take the time to watch it. Flashing requires an ST-LINK V2 and connection is via the below image.
EWRF E7082VM V1 & V2 - Max output power of +500mW.
OpenVTx uses VS Code and PlatformIO.
Big thanks to cruwaller for adding the GD32 MCU found on the EWRF E7082VM, and everyone else!
