£9.90
This product will be useful for people requiring PWM outputs from their ExpressLRS or Crossfire radio receiver. It converts from CRSF, which is the protocol used by ExpressLRS and Crossfire receivers, to PWM outputs which is the signal used to drive servos and ESCs. This particular breakout board provides 6 PWM connections and PWM output frequency can be adjusted for faster servos (50Hz default, 100, 160, 330, 400Hz) – if you need more connections, Matek make a 10-channel version which also includes on board current sensor. In addition to the PWM connections, the board provides 2x uarts to allow for connection of a GPS receiver (NMEA output), which then transmits the coordinates along with the Crossfire Telemetry. The board is compatible with up to 36v input, but please note this doesn’t power the servo rail, instead you should power from an external source e.g. a 5v ESC UBEC or external voltage regulator .
Please note, this listing is just for the converter and doesn’t include a receiver as pictured in the images below.
Pinouts and Pads
Tx1/Rx1(UART1) for CRSF protocol Receiver
Tx2/Rx2(UART2) for GPS/firmware update/setting parameters
1~10: CH1~CH10 PWM outputs
Curr: current sensor signal (0~3.3V)
Vbat: Battery voltage sensing (0~36V)
G: ground
4v5 pad voltage = 5V pad voltage -0.3V, make sure the voltage on 5V pad is not higher than receiver and GPS rated voltage.
Failsafe
Failsafe value is set automatically after CRSF-PWM board is powered on and receive CRSF signal. LED blinks 8 times quickly.
Failsafe value = The PWM value of each channel(except CH3) when CRSF signal is received by CRSF-PWM board for the first time
CH3 is specially arranged for the throttle, Failsafe value = 988 by default.
Usually put the Throttle joystick to the lowest point, put AIL(Roll), ELE(Pitch), RUD(Yaw) middle before powering on receiver.
LED status
slow blinks: CRSF-PWM board doesn’t receive CRSF signal, e.g., receiver is not bound with transmitter, receiver is not connected to UART1 of CRSF-PWM board.
8x quick blinks: CRSF-PWM board received CRSF signal and failsafe value is saved.
solid ON: CRSF-PWM board and receiver are working normally
2x slow blinks between 8x fast blink and solid on: CLI mode is active
GPS telemetry
Compatible with GPS NMEA protocol, 1Hz, Baud 9600~115200
GPS “TX” to CRSF-PWM board “RX” Single wire half duplex UART connection, CRSF-PWM board “TX” to GPS “RX” is not essential.
Support GPS Telemetry ID: GPS, GSpd, Hdg, Alt, Sats
u-blox series GPS can output “0+1 – UBX+NMEA” protocol by default
Sensors(GPS, GSpd, Hdg, Alt, Sats) will blink in Transmitter TELEMETRY tab once CRSF-PWM board has connection with GPS.
Troubleshooting for no GPS telemetry, double check the wiring between GPS and CRSF-PWM board, some u-blox GPS may don’t output NMEA protcol, you need to be reverted GPS to default configuration in u-center.
with OpenTX Telemetry Logging , You can plot your flight path or search the lost plane.
TIM & PWM Frequency
PWM frequency on all 10x Channels can be configured according to TIM
PWM run at 50Hz by default
TIM2: CH1, CH2, CH4
TIM16: CH3
TIM3: CH5, CH6, CH7, CH8
TIM1: CH9, CH10
CLI mode
If CRSF-PWM board doesn’t detect GPS connected to UART2 within 10 seconds after powering on, CLI mode will active.
After CLI mode is active, CRSF-PWM board can be connected to configurator via USB-TTL module/FC passthrough.
in CLI mode, CRSF-PWM board firmware can be updated
CLI mode has no effect to receiver CRSF signal and PWM outputs