ExpressLRS manual for SIYI FM30 and FRmini 2.4 GHz - 23-4-2021-rev 2 by Jupa Creations

Equip SIYI FM30 TX and FRminiRX with ExpressLRS firmware based on Windows based OS.

ExpressLRS also called ELRS is evolving rapidly, to stay tuned you better opt to go to the Discord server

where all developers and main users are gathered.

This manual is written based on information available on 23-4-2021

There are different levels of ELRS firmware designs.

Currently we use the firmware for the TX, RX from the “OFFCIAL RELEASES” section which can be easily

flashed with the ELRS configurator.

You can’t mix and match firmware from the “OFFICIAL RELEASES” and “GIT BRANCH” sections.

Once a 2.4 gHz product is flashed with the same version firmware you can mix and match with other brands

TX and RX.

Warning: This is a not reversable firmware change step. Original SIYI firmware cannot be restored anymore!

Hardware

Order a “ST-LINK V2”.

Although hard to request from sellers the RST pin output should work. SomeST-link devices(Chinese based

companies) are prone to not have this RST pin working / connected!

If your ST-Link has a not working RST pin output, see the “ST-Link RST pin workaround” at the end of this

document.

I ordered this ST-Link form a Dutch web shop which luckily worked in my case.

https://www.tinytronics.nl/shop/nl/communicatie/usb/st-link-v2-stm8stm32-compatible

ExpressLRS manual for SIYI FM30 and FRmini 2.4 GHz - 23-4-2021-rev 2 by Jupa Creations

Software

1] Download the latest ExpressLRS configurator from Github.

https://github.com/ExpressLRS/ExpressLRS-Configurator

Click at the right hand of the screen side on the green button “Latest”.

Select the “ExpressLRS-Configurator-Setup-0.4.XX.exe” file and install it.

We used configurator version 4.13

2] When the program is installed open the ELRS configurator

Select the “FM30_TX_via_STLINK” from “device target”.

The “DOWNLOAD LUA SCRIPT” link appears.

Click on the link .

A “Windows Explorer” screen opens automatically.

Copy the “ELRS.lua” file onto the TX SD-card in the “Scripts/Tools” folder.

TX

Open the SIYI FM30 module by removing the 4 small screws at the corners.

Use a small Philips head screwdriver.

Lift the cover plate from the module case.

Remove the antenna holder from the cover by unscrewing the nut.

Remove the 2 screws around the middle edges and remove the PCB from the module case.

Solder 4 thin wires to the JP4 holes.

CLK-DIO-RST-GND.

Solder one wire to the VCC pad.

ExpressLRS manual for SIYI FM30 and FRmini 2.4 GHz - 23-4-2021-rev 2 by Jupa Creations

Solder the open ends preferable to a female 2.54 mm header.

Connect the ST-Link with male-female jumper wires to the temporary connector from the SIYI FM30 TX board.

ST-Link <> FM30

DIO <> DIO

CLK <> CLK

GND <> GND

RST <> RST

5V <> VCC < Note the voltage used.

Connect the ST-Link to the PC. There will be no LED light on the FM30.

Go the ELRS configurator program.

Click on

“Click on the tab “OFFICIAL RELEASE” and select “1.0.0-RC1“ from the dropdown menu.

If a newer version is available use this version.

ExpressLRS manual for SIYI FM30 and FRmini 2.4 GHz - 23-4-2021-rev 2 by Jupa Creations

Select the “FM30_TX_via_STLINK”from “device target”.

At “Device options”, fill in a minimum 6 character “Custom binding phrase”.

Tick the boxes for “FEATURE_OPENXT_SYNC” as a basic setting.

If needed thick the other boxes if needed.

Settings can later be altered with the UPDATE function.

At “Actions”, click on “BUILD&FLASH” and wait for the configurator to work its way through it.

If you are using the ELRS configurator the first time files are downloaded and installed in the background. This

may take a minimum 7+ minutes. DO NOT ABORT and wait with patience, it is worth it.

When “Success” is displayed. Your now ready with the TX.

If you have a failure using the previous steps use the following option only once. This takes time and upload

bandwidth for everyone involved!

ExpressLRS manual for SIYI FM30 and FRmini 2.4 GHz - 23-4-2021-rev 2 by Jupa Creations

Click on

Click on

Removing these PlatformIO Dependencies may take a few minutes. DO NOT ABORT!!

If you used VS and PIO before for example 3D printers and run into problems use the “CLEAR PLATFORMIO

DEPENDENCIES” only once.

Start the “BUILD & FLASH” option again.

If you have continuous errors use the Discord server“help and support” section to trouble shoot with other

FM30 users.

Desolder the wires and connector as for further flash and updates we will use the convenient USB port on the

FM30 module onwards only.

Assemble the FM30 module in reverse order and place it in your transmitter.

RX

If you do not have correct solder equipment (fine tip solder point) or skills do not proceed.

You are advised to buy another brand readymade and pre flashed receivers like for example shown below.

The flash solderpads on the FRmini RX are very tiny and very close together.

The picture below is enlarged, so in real life they are very tiny.

Solder 5 (preferable Silicon) wires to the GND-RST-VDD-CLK-DIO pads.

Solder the open ends to a female 2.54 mm pin connector.

ExpressLRS manual for SIYI FM30 and FRmini 2.4 GHz - 23-4-2021-rev 2 by Jupa Creations

Connect the ST-Link with jumper wires to the 5 wires from the SIYI FRmini board.

ST-Link <> FR mini

DIO <> DIO

CLK <> CLK

GND <> GND

RST <> RST

3.3V <> VDD < Note the voltage used.

Go to the ELRS configurator.

Click on

“Click on the tab “OFFICIAL RELEASE” and select “1.0.0-RC1“ from the dropdown menu.

If a newer version is available use this version.

Select the “FM30_RX_MINI_via_STLINK” from “device target”.

ExpressLRS manual for SIYI FM30 and FRmini 2.4 GHz - 23-4-2021-rev 2 by Jupa Creations

3] at “Device options”, fill in a minimum 6 character “Custom binding phrase”.

Make sure the selected options at the RX are the same as the previous flashed TX.

4] At “Actions”, click on “BUILD & FLASH” and wait for the configurator to work its way through it.

This will take less time as PlatformIO and other programs are already installed.

When “Success” is displayed. You are ready with the RX.

If you have an error use the Discord server “help and support” section to trouble shoot with other FM30 users.

Remove the soldered wires carefully.

BINDING

Power the FM30 TX and the FRmini RX and they will bind automatically due to the “Custom Bind Phrase” used.

ExpressLRS manual for SIYI FM30 and FRmini 2.4 GHz - 23-4-2021-rev 2 by Jupa Creations

RX connection to Flight controller

Connect 2 silicone wires to the FRminiTX2 and RX2 pads.

Connect 2 wires to GND and VDD (5V) at the large holes.

Do not use the VDD from the 5 in a row pads used for flashing!

ExpressLRS manual for SIYI FM30 and FRmini 2.4 GHz - 23-4-2021-rev 2 by Jupa Creations

Connect the 4 wires to a free UART port on your Flight controller. And set this port up for Serial connection in

for example Inav or Betaflight.

FC FRmini

TX FREE <> RX2

RX FREE <> TX2

GND <> GND

5V <> VDD

After the first flash of the TX and RX by ST-Link you now can use a different “Update” method without the use

of the ST-Link.

TX update

For the FM30 module

Close programs that work with a serial port like Inav, Betaflight and so on.

1] Hook up a USB mini cable to the module.

2] Press the BIND button on the module and place the other end of the USB cable in the PC.

3 ] Use the ELRS configurator as before but choose as target “FM30_TX_via_DFU”.

4] Click “BUILD & FLASH”.

When finished you currently get a “Flash Error”.

You can ignore this message as long as download success

ExpressLRS manual for SIYI FM30 and FRmini 2.4 GHz - 23-4-2021-rev 2 by Jupa Creations

RX update

For the FRmini

1 ] Hook up an USB cable between the flight controller and the PC and power the flight controller with a

battery too.

2 ] Close all programs that work with a serial port. Inav, Betaflight and so on.

3 ] Use the ELRS configurator as before but choose as target “FM30_RX_via_BetaflightPassthrough”.

4] Click “BUILD & FLASH”.

ELRS LUA script

To run the ELRS LUA script from the SD card long Press the "SYS" button (for T16 or similar Radios) or the

"Menu" button (for Taranis X9D or similar Radios) to access the Tools Menu where you can find ELRS script

ready to run with only one click.

From the 0:150 value in the top the 150 must correspond with the Pkt. Rate setting in Hz.

The left-hand side number is the number of error packages. If this value is continuously larger as 0 (Zero) you

have a problem.

Maximum Power setting for the FM30 module is 100mW which in many cases is more than enough with ELRS.

To accomplish correct communication with the ELRS LUA script your TX firmware should be flashed with the

OPENTX-Nightly version which can be downloaded from here.

From OPENTX version 2.4 ELRS is fully supported.

When you change settings in the ELRS LUA script, it is advised to power cycle the TX and RX once.

If you use telemetry and your frequently get “Sensor lost/Telemetry lost” messages through OPENTX reduce

the “TLM Ratio” from for example 1:128 to the next lower setting like 1:64 – 1:32 – 1:16 – 1:8 -1:4 one by one.

If the last used setting is not giving the “Sensor lost/Telemetry lost” message anymore leave it at this setting.

When “TLM Ratio” is switched ON, this option is in a ratio also sending a telemetry package after sending a

number of RC control packages.

So for 1:128 it sends after 128 RC control packages 1 telemetry package.

The lower the ratio the often the sensor info is transmitted from RX to TX.

For flying planes at for example a Pkt. Rate @ 50hZ and TLM RATIO 1:16 you have full control and telemetry.

If you fly quads and do not need telemetry on your OPENTX TX switch this function to “OFF”.

ExpressLRS manual for SIYI FM30 and FRmini 2.4 GHz - 23-4-2021-rev 2 by Jupa Creations

Setting up Telemetry for the TX is the same as for regular OPENTX users.

First “Delete all sensors”.

Then “Discover new sensors”.

ExpressLRS manual for SIYI FM30 and FRmini 2.4 GHz - 23-4-2021-rev 2 by Jupa Creations

Take care that when you delete and rediscover sensors the numbering order of the sensors might change.

So if you use the sensor data for optical and voice messages they might be wrong.

This is the current behaviour for ELRS in combination with Telemetry that can’t be changed.

ST-Link RST pin workaround

If the ST-Link RST pin is not working, you need to download the STM32-Utility from here.

When the STM32-Utility is installed open the program and hoover your mouse over the “Connect” button.

Click the “Connect” button and tap the RST wire connected at the FM30 RST pin to the other free GND of the

ST-link.

If done within reasonable time, you get a pop-up warning.

After that click “Disconnect” in the STM32-Utility.

Now just flash the firmware as described with the ELRS configurator

Repeat the same steps for the FRmini.

HAPPY FLYING…

Interesting links:

Github

https://github.com/ExpressLRS

Discord server

https://discord.gg/Swypv3uDnZ