Description

**FIRMWARE UPDATE

ELRS CRSF TO SBUS CONVERTER

Specifications

• Compatible with CRSF/SBUS protocol receiver.
• Support CRSF to SBUS, or SBUS to CRSF conversion
• Battery voltage(RxBt) telemetry over CRSF protocol
• CRSF to SBUS latency <7ms
• Rated voltage: 4~5.5V @5V pad,  0~36V @VBAT pad
• No 5V regulator built-in,  VBAT pad is just for battery voltage sensing.
• PCB size 15mm x 10mm,  0.6g
• 2pcs/package

LED status

• slow blinks: CRSF-SBUS board doesn’t receive CRSF or SBUS signal, e.g., receiver is not bound with transmitter, receiver is not connected to UART of CRSF-SBUS board.
• solid ON:  CRSF-SBUS board and receiver are working normally.

Package Contents ::

• 2pcs x ELRS CRSF TO SBUS CONVERTER

FIRMWARE UPDATE GUIDE

• Tool: Matek Configurator
• Firmwares: crsf_sbus_fw.zip
• Mar.19,2022,  v1.1.0:  Fixed a failsafe bug when CRSF-SBUS converter can’t get CRSF signal from receiver.

Upgrade CRSF-SBUS via A or B

A. USB-TTL modules,  such as CP210x,  FTDI

1. Wiring

• TX1  —  USB-TTL module RX
• RX1  —  USB-TTL module TX
• 5V  —  USB-TTL module 5V
• G  —  USB-TTL module GND

2. Bridge the jumper pad at bottom side with a drop of tin,  or bridge it with tips of tweezer when powering on.

3. Connect USB-TTL module to PC,

Blue LED on CRSF-SBUS board will blink fast,  it means CRSF-SBUS board is working in boot mode.

now you can remove the jumper or remove it after flashing.

4. Open Matek configurator,  Select COM port of USB-TTL, Baud rate 115200,  Click “Connect”

5. OpenFile “crsf_sbus_vx.x.x.bin”

6. Click “Upgrade”

7. After update, remove the jumper.

B. INAV/BF serial passthrough

1. Wiring

• TX1  —  FC any spare UART_RX
• RX1  —  FC any spare UART_TX
• 5V  —  FC 5V or 4V5
• G  —  FC GND

2. Bridge the jumper pad at bottom side with a drop of tin,  or bridge it with tips of tweezer when powering on.

3. Connect FC USB to PC

Blue LED on CRSF-SBUS board will blink fast,  it means CRSF-SBUS board is working in boot mode.

now you can remove the jumper or remove it after flashing.

4. open INAV/BF configurator, connect FC to configurator

5. click INAV/BF configurator “CLI” tab, type “serialpassthrough x 115200”,  x = UART number -1,  e.g. CRSF-SBUS board connect to FC UART4,  type “serialpassthrough 3 115200”.

6. Disconnect FC from configurator, make sure USB is still plugged in FC and LED on CRSF-SBUS board is still blinking fast.

7. Open Matek configurator,  Select COM port of Flight controler,  Baud rate 115200,  Click “Connect”

8. OpenFile “crsf_sbus_vx.x.x.bin”

9. Click “Upgrade”

10. After update, remove the jumper.