Matek CRSF-PWM-C TBS Crossfire to PWM converter

CRSF-PWM Converter, CRSF-PWM-C

• Compatible with CRSF protocol receiver only
• 10x PWM outputs
• PWM frequency configurable (50Hz default, 100,160,330, 400Hz)
• 2x UARTs (for Receiver and GPS)
• Telemetry ID: RxBt, Curr, Capa, Bat%, GPS, GSpd, Hdg, Alt, Sats
• 36V Max. battery voltage sense (1K:10K voltage divider built-in)
• Current sensor built-in (90A continuous /220A Peak), current scale = 150 by default
• Vbat and Current sensor scale configurable
• Failsafe value auto set
• Firmware upgradeable
• Rated voltage: 4~9V @5V pad, 0~36V @BAT+
• No 5V regulator built-in
• 26mm x 26mm, 2.8g
• Packing: 1x CRSF-PWM-C, 1x low ESR capacitor, Dupont 2.54 pins

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
• 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.

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

• Tool: Matek Configurator
• via A or B

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

1. Wiring

• TX2 — USB-TTL module RX
• RX2 — USB-TTL module TX
• 4v5 — USB-TTL module 5V
• G — USB-TTL module GND

2. Connect USB-TTL module to PC

3. CRSF-PWM board CLI mode will active after powering on for 10 seconds

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

5. Type command “help”

B. INAV/BF serial passthrough

1. Wiring

• TX2 — FC any spare UART_RX
• RX2 — FC any spare UART_TX
• 4v5 — FC 5V or 4V5
• G — FC GND

2. Connect FC USB to PC

3. CRSF-PWM board CLI mode will active after powering on for 10 seconds

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-PWM board connect to FC UART4, type “serialpassthrough 3 115200”.

6. Type command “help”

help

List all commands

• help
• version
• reboot
• get failsafe
• get channel
• get tim
• get scale
• get battery
• set tim[n] = [x](n:1,2,3,16; freq:50,100,160,330,400)
• set vbat_scale = [x](60 – 210)
• set current_scale = [x](50 – 500)

version

list CRSF-PWM firmware version

• CRSF_PWM App v0.9.5(Sep 25 2021)

reboot

restart CRSF-PWM board

• If receiver is connected and bound to transmitter, Failsafe value will be reset according to the transmitter joystick position.

get failsafe

list failsafe value saved

• PWM CH1_failsafe = 1500;
• PWM CH2_failsafe = 1500;
• PWM CH3_failsafe = 988;
• PWM CH4_failsafe = 1500;
• PWM CH5_failsafe = 1000;
• PWM CH6_failsafe = 1000;
• PWM CH7_failsafe = 1000;
• PWM CH8_failsafe = 1000;
• PWM CH9_failsafe = 2000;
• PWM CH10_failsafe = 2000;

get channel

list all channels PWM value according to joystick position if receiver is connected and bound to transmitter

If receiver is not connected or not bound to transmitter, the CH PWM value = failsafe value saved

• CH1 = 1502;
• CH2 = 1500;
• CH3 = 1007;
• CH4 = 1498;
• CH5 = 1000;
• CH6 = 1000;
• CH7 = 1000;
• CH8 = 1000;
• CH9 = 2000;
• CH10 = 2000;

get tim

list PWM frequency on all TIM

• TIM2 = 50Hz (CH1,2,4);
• TIM16 = 50Hz (CH3);
• TIM3 = 50Hz (CH5,6,7,8);
• TIM1 = 50Hz (CH9,10);

set tim[n] = [x](n:1,2,3,16; freq:50,100,160,330,400)

set PWM frequency on each TIM/CH

• “n” range: 1, 2, 3, 16
• “[x]” range: 50, 100, 160, 300, 400
• TIM2: CH1, CH2, CH4
• TIM16: CH3
• TIM3: CH5, CH6, CH7, CH8
• TIM1: CH9, CH10
• 50Hz by default. Compatible with both old school and modern PWM ESC/servos
• Check ESC and servos datasheet to make sure the ESC and servos can work stably at that PWM frequency you will set.
• Usually Analog servos work at 50Hz only, some digital servos can work at 400Hz. ESC supported by oneshot/DShot can work at 400Hz PWM
• e.g. type “set TIM16 = 400”, PWM output on CH3 will be 400Hz
• e.g. type “set TIM2 = 100”, PWM output on CH1, CH2,CH4 will be 100Hz

get scale

• vbat_scale = 110;
• current_scale = 150;

get battery

list Battery voltage and current, Even if there is no current through the shunt resistor, there may be a certain current reading due to the offset and tolerance of current sensor.

• voltage = 0(mV);
• current = 0(mA);

set vbat_scale = [x](60 – 210)

• 1K:10K resistor: 110 by default
• Because of components tolerance you can adjust this to match with multimeter readout.

set current_scale = [x](50 – 500)

• current_scale = 150 by default
• If current readout 10A on telemetry, 10.8A on current meter, you can set the scale to (10.8/10)*150=162