MinOPOSD setup


Some years ago Joerg-D. Rothfuchs (JR63) added UAVTALK protocol to minimOSD firmware to allow communication between MinimOSD and OpenPilot boards.The MinOPOSD is born.

Useful info still available in the following pages:

The OSD (On Screen Display) enables useful information to be superimposed on a video signal to an FPV pilot.

Connection diagram

In this page


All OpenPilot and LibrePilot releases supported.


Board supported

Analog inputsFirmware file

All analog inputs connected to OSD board.

RSSI, Vbat, Current. MinimOSD or Micro KV Team

Needed for CC3D who can't support current sensor.

All boards


Rssi, Vbat,


Nothing connected to OSD hardware, all information comes from flight controller.

RSSI information comes from link quality UAVO.

Voltage/current sensor can be connected to Revolution board,

See Configure a Current-Voltage sensor

Revo only


Same as above

Voltage/current sensor connected to Revo

+ analog RSSI connected to OSD.

Revo only


The config tool used for OSD configuration : ConfigTool_minOPOSD.zip

First time you update the MinimOSD board you may need the charset : Charset_1_3_0.mcm

MinopOSD source code is here.

Hardware connections

All boards

Communication between flight controller and OSD is done using a serial telemetry at 57600bauds.

JST connector

Main / Flexi port

Connector pin (board)




Please note Tx/Rx lines are crossed

Configure one port with telemetry at 57600bauds, can be MainPort or FlexiPort.


Revolution only

Revolution board can provide extra telemetry on FlexiIO port (receiver port), for normal operation no need the DTR pin wired.

JST connector

Revolution FlexiIO

Connector pin (board)



9 (for programming)DTRGRN or DTR

Two options are available for telemetry output on FlexiIO (receiver) port:



Programming setup

Using Revolution board

With the Revolution board you can use the FlexiIO port for telemetry and optional DTR pin is wired with MinimOSD.

Please note the programming cannot be done without DTR pin wired.

First you need to setup Revolution board as follows :

1 - Connect Revolution board to the computer

2 - Go to the Configuration Tab and Hardware tab

3 - For USB VCP function, select ComBridge

4 - In Receiver Port, select ComBridge

5 - Save and reboot board

Now you can connect the receiver port with the minimOSD board, be sure the revolution board is powered with 5V

Using a FTDI device

 Connect FTDI device with MinimOSD as follow

Firmware upload

There is two chips on MinimOSD board, one is a Atmel 368P and the other is a MAX7456 (video chip)

Download and extract archive: ConfigTool_minOPOSD.zip

This is a standalone application and so doesn't require further installation.

Start the config tool:

Update charset

First update character set stored inside MAX7456 chip, be sure the video side is also powered. Some MinimOSD board need +12v on video side or 5v mods.

1 - Select the right port, in this example COM1

2 - Go to Options menu and Update Charset...

3 - Select the character set file (Charset_1_3_0.mcm) where you saved it on your hard drive.

4 - Wait the process is complete, this can take some time.

 About charset file...

Character set contains all characters used by the MAX7456 chip, it should be updated or OSD display can be wrong like letters or others exotic characters shown.



Update firmware

1 - Select the right port, in this example COM1

2 - Go to Options menu and Update Firmware...

3 - Select the firmware file (.hex) where you saved it on your hard drive. See Downloads.

4 - Wait the process is complete.


OSD configuration

Video standard

Video standard can be PAL or NTSC, selected by software and MinOPOsd talk with video chip to apply changes.

Go to Video Mode menu and select PAL or NTSC according to the camera used.

Don't forget the Save current tab to button to apply changes.

PAL preview
NTSC preview
PAL:16lines x 30columnsNTSC: 13lines x 30columns

Channel toggle

Channel toggle has two functions :

  • Allow screen switching between Panel1, Panel2 and a empty panel.
  • Enter Setup screen just after boot

Note the default panel is Panel1 while any alarm is active: (DISARMED,LINK QUALITY, LOW BATTERY...) and you cannot switch to other screen/panel.

Disabled: No screen changes, stay in Panel 1

Mode Switch: Uses the FlightMode switch, if you switch from a FlightMode to another than back within 2 sec, than will jump to the next screen.

Ch5 to Ch8: Assign a channel for screen switching, should be 3 positions switch. Those "Channels" do not refers to real channel found in RC receiver but mapped like this:

  • Ch5: The flight mode switch (this means you can see for example Panel1 in Attitude mode, Panel2 in Rate mode and empty screen in Rattitude mode),
  • Ch6: The Accessory0 as defined in Input tab,
  • Ch7: The Accessory1 as defined in Input tab,
  • Ch8: The Accessory2 as defined in Input tab.

Rotation Switching option: When checked, a momentary switch can be used (Ch5 to Ch8 defined). Every time you move switch OSD jump to next screen. Panel1, Panel2, Empty, Panel1...

Rssi setup

Only used with analog Rssi input pin

See https://code.google.com/p/minoposd/wiki/AnalogRSSI how to setup hardware and calibrate.


Battery settings

Defines the level that triggers the "Low battery" alarm.


Panel setup

Select information to be displayed in the left list and place it on the grid.

Save current tab to button to apply changes.

There is some custom information in LibrePilot firmware, for example the "Temperature" field can display the barometer temperature (Revo boards) or TxPID values (useful when TxPID-EasyTune is used). See Rc OSD setup


RC OSD setup

Some parameters can be modified using the Rc transmitter, toggle switch and Pitch/roll stick.

Just after boot, move the Toggle switch and you enter the Setup screen. Pitch stick change parameter while Roll stick allow parameter/value adjustment:

  • UAVTALK : Active or passive,
  • TEMPDISP: Choose Baro temperature or TxPID values display for the "Temperature" field,
  • BATTERY WARNING: adjust battery level.

Only with firmware using analog inputs:

  • CALIBRATE: monitor volt/amp values and adjust factors/amp offset
    • Measured volt: Volt div ratio
    • Measured amps: Amps offset
    • Measured amps: Amps per volt

Refresh rates

Refresh rates should be fine for normal (flight) use. For setup screen changes and easy stick response you should modify ManualControlCommand refresh rate.

1 - Go to System tab

2 - In UAVOBrowser click View options button and check Show Metadata

3 - Browse the the "Data" part and find ManualControlCommand UAVO

4 - Click the little arrow close to the Meta Data field

5 - Change Flight Telemetry Update Period to something lower, like 250ms

6 - Save changes

Others UAVObject rates can be modified and lowered as well, for smooth position and velocity changes:

  • GPSPositionSensor
  • GPSVelocitySensor