# VOXL FPV Racing 4-in-1 ESC with flight core v2 and voxl2

Source: https://forum.modalai.com/topic/4364/voxl-fpv-racing-4-in-1-esc-with-flight-core-v2-and-voxl2
Category: General Questions (https://forum.modalai.com/category/2/general-questions)
Posted: 2025-04-21 09:58:18 UTC by Jetson Nano
Replies: 30 · Views: 6372

## Jetson Nano · 2025-04-21 09:58:18 UTC

Hello @Eric-Katzfey @Alex-Kushleyev @tom 
I am using voxl2 , with flight core v2 and VOXL FPV Racing 4-in-1 ESC. I would like to know how to setup this pipeline. what are the parameters that requires to be changed and what are values.
could anyone help me this approach
The Flight controller is not recognising the ESC.

## Reply by Eric Katzfey (ModalAI staff) · 2025-04-21 14:57:22 UTC

@Jetson-Nano Are you using PX4 on the flight core v2? If so, what version? What do you mean when you say that it is not recognizing the ESC?

## Reply by Jetson Nano · 2025-04-21 17:07:21 UTC (in reply to Eric Katzfey)

@Eric-Katzfey i am using  http://voxl-packages.modalai.com/dists/fc-v2/dev/modalai_fc-v2_1.14.0-2.0.95.px4 version and also tried with  http://voxl-packages.modalai.com/dists/fc-v2/dev/modalai_fc-v2_1.14.0-2.0.90.px4.
The ESC should start blinking blue LED to represent achieving data from FC. It is not happening.

## Reply by Eric Katzfey (ModalAI staff) · 2025-04-21 22:40:02 UTC (in reply to Jetson Nano)

@Jetson-Nano How are the VOXL_ESC parameters set on your FCv2? There could be a UART baud rate mismatch between what FCv2 is using and what the ESC is using.

## Reply by Alex Kushleyev (ModalAI staff) · 2025-04-22 04:04:24 UTC (in reply to Eric Katzfey)

@Jetson-Nano , if the voxl_esc driver is started by PX4 running on the Flight Core, it should print out debugging information to the UART console. The log below was taken from PX4 running on VOXL2 DSP, but the output should be the same when using Flight Core V2.

Please also note that the Flight Core (V2), when powered up, starts immediately (as opposed to VOXL2 booting takes a few seconds), so FC V2 will try to detect the ESC before the ESC exits bootloader (which takes 1 second after power is applied) and will fail to detect the ESC.  This was fixed in our FC V2 drone config, please check your voxl-esc driver behavior. Here is the commit that added the delay of 1.5 seconds before starting voxl esc driver on FC V2: 

- https://github.com/modalai/px4-firmware/pull/70/commits/55742d298bf9241a2af5aa2c7ba3a26788073356
- https://github.com/modalai/px4-firmware/pull/70/commits/1c11e2e0ac3fcc19cb45ab59292b3cf5f4fdb348

(voxl-esc driver log from VOXL2 DSP is below)
```
INFO  [muorb] SLPI: VOXL_ESC: Starting VOXL ESC driver
INFO  [muorb] SLPI: VOXL_ESC: Opening UART ESC device 2, baud rate 2000000
INFO  [muorb] SLPI: VOXL_ESC: Successfully opened UART ESC device
INFO  [muorb] SLPI: VOXL_ESC: Detecting ESCs...
INFO  [muorb] SLPI: VOXL_ESC: 	ESC ID     : 0
INFO  [muorb] SLPI: VOXL_ESC: 	Board Type : 37: ModalAi 4-in-1 ESC (M0134-1)
INFO  [muorb] SLPI: VOXL_ESC: 	Unique ID  : 0x203330385246571900480024
INFO  [muorb] SLPI: VOXL_ESC: 	Firmware   : version   39, hash eb6fb500
INFO  [muorb] SLPI: VOXL_ESC: 	Bootloader : version  183, hash b4fa2cf8
INFO  [muorb] SLPI: VOXL_ESC: 	Reply time : 1646us
INFO  [muorb] SLPI: VOXL_ESC:
INFO  [muorb] SLPI: VOXL_ESC: 	ESC ID     : 1
INFO  [muorb] SLPI: VOXL_ESC: 	Board Type : 37: ModalAi 4-in-1 ESC (M0134-1)
INFO  [muorb] SLPI: VOXL_ESC: 	Unique ID  : 0x2033303852465719004D004D
INFO  [muorb] SLPI: VOXL_ESC: 	Firmware   : version   39, hash eb6fb500
INFO  [muorb] SLPI: VOXL_ESC: 	Bootloader : version  183, hash b4fa2cf8
INFO  [muorb] SLPI: VOXL_ESC: 	Reply time : 621us
INFO  [muorb] SLPI: VOXL_ESC:
INFO  [muorb] SLPI: VOXL_ESC: 	ESC ID     : 2
INFO  [muorb] SLPI: VOXL_ESC: 	Board Type : 37: ModalAi 4-in-1 ESC (M0134-1)
INFO  [muorb] SLPI: VOXL_ESC: 	Unique ID  : 0x203330385246571900500042
INFO  [muorb] SLPI: VOXL_ESC: 	Firmware   : version   39, hash eb6fb500
INFO  [muorb] SLPI: VOXL_ESC: 	Bootloader : versiINFO  [qshell] Send cmd: 'voxl_esc start'
INFO  [muorb] SLPI: VOXL_ESC: 	Reply time : 1120us
INFO  [muorb] SLPI: VOXL_ESC:
INFO  [muorb] SLPI: VOXL_ESC: 	ESC ID     : 3
INFO  [muorb] SLPI: VOXL_ESC: 	Board Type : 37: ModalAi 4-in-1 ESC (M0134-1)
INFO  [muorb] SLPI: VOXL_ESC: 	Unique ID  : 0x2033303852465719004D0050
INFO  [muorb] SLPI: VOXL_ESC: 	Firmware   : version   39, hash eb6fb500
INFO  [muorb] SLPI: VOXL_ESC: 	Bootloader : version  183, hash b4fa2cf8
INFO  [muorb] SLPI: VOXL_ESC: 	Reply time : 617us
INFO  [muorb] SLPI: VOXL_ESC:
INFO  [muorb] SLPI: VOXL_ESC: Use extened rpm packet : 1
INFO  [muorb] SLPI: VOXL_ESC: All ESCs successfully detected
```

## Reply by Jetson Nano · 2025-04-22 04:06:57 UTC (in reply to Alex Kushleyev)

@Alex-Kushleyev Thank you for reverting back. I will verify this and get back.

I changed the firmware version to the ```voxl-fpv-dev``` still the FC is not detecting the ESC. 

if i start esc through voxl_esc start , it is starting

could please verify the parameters I mentioned.

```
nsh> voxl_esc status
INFO  [voxl_esc] Max update rate: 0 Hz
INFO  [voxl_esc] Outputs on: no
INFO  [voxl_esc] UART port: /dev/ttyS4
INFO  [voxl_esc] UART open: no
INFO  [voxl_esc] 
INFO  [voxl_esc] Params: VOXL_ESC_CONFIG: 1
INFO  [voxl_esc] Params: VOXL_ESC_MODE: 0
INFO  [voxl_esc] Params: VOXL_ESC_BAUD: 250000
INFO  [voxl_esc] Params: VOXL_ESC_FUNC1: 101
INFO  [voxl_esc] Params: VOXL_ESC_FUNC2: 104
INFO  [voxl_esc] Params: VOXL_ESC_FUNC3: 102
INFO  [voxl_esc] Params: VOXL_ESC_FUNC4: 103
INFO  [voxl_esc] Params: VOXL_ESC_SDIR1: 0
INFO  [voxl_esc] Params: VOXL_ESC_SDIR2: 0
INFO  [voxl_esc] Params: VOXL_ESC_SDIR3: 0
INFO  [voxl_esc] Params: VOXL_ESC_SDIR4: 0
INFO  [voxl_esc] Params: VOXL_ESC_RPM_MIN: 5500
INFO  [voxl_esc] Params: VOXL_ESC_RPM_MAX: 15000
INFO  [voxl_esc] Params: VOXL_ESC_T_PERC: 90
INFO  [voxl_esc] Params: VOXL_ESC_T_DEAD: 20
INFO  [voxl_esc] Params: VOXL_ESC_T_EXPO: 35
INFO  [voxl_esc] Params: VOXL_ESC_T_MINF: 0.150000
INFO  [voxl_esc] Params: VOXL_ESC_T_COSP: 0.990000
INFO  [voxl_esc] Params: VOXL_ESC_VLOG: 0
INFO  [voxl_esc] Params: VOXL_ESC_PUB_BST: 1
INFO  [voxl_esc] Params: VOXL_ESC_T_WARN: 0
INFO  [voxl_esc] Params: VOXL_ESC_T_OVER: 0
INFO  [voxl_esc] Params: GPIO_CTL_CH: 0
INFO  [voxl_esc] 
INFO  [voxl_esc] -- ID: 0
INFO  [voxl_esc]    Motor:           1
INFO  [voxl_esc]    Direction:       1
INFO  [voxl_esc]    State:           0
INFO  [voxl_esc]    Requested:       0 RPM
INFO  [voxl_esc]    Measured:        0 RPM
INFO  [voxl_esc]    Command Counter: 0
INFO  [voxl_esc]    Voltage:         0.000000 VDC
INFO  [voxl_esc] 
INFO  [voxl_esc] -- ID: 1
INFO  [voxl_esc]    Motor:           4
INFO  [voxl_esc]    Direction:       1
INFO  [voxl_esc]    State:           0
INFO  [voxl_esc]    Requested:       0 RPM
INFO  [voxl_esc]    Measured:        0 RPM
INFO  [voxl_esc]    Command Counter: 0
INFO  [voxl_esc]    Voltage:         0.000000 VDC
INFO  [voxl_esc] 
INFO  [voxl_esc] -- ID: 2
INFO  [voxl_esc]    Motor:           2
INFO  [voxl_esc]    Direction:       1
INFO  [voxl_esc]    State:           0
INFO  [voxl_esc]    Requested:       0 RPM
INFO  [voxl_esc]    Measured:        0 RPM
INFO  [voxl_esc]    Command Counter: 0
INFO  [voxl_esc]    Voltage:         0.000000 VDC
INFO  [voxl_esc] 
INFO  [voxl_esc] -- ID: 3
INFO  [voxl_esc]    Motor:           3
INFO  [voxl_esc]    Direction:       1
INFO  [voxl_esc]    State:           0
INFO  [voxl_esc]    Requested:       0 RPM
INFO  [voxl_esc]    Measured:        0 RPM
INFO  [voxl_esc]    Command Counter: 0
INFO  [voxl_esc]    Voltage:         0.000000 VDC
INFO  [voxl_esc] 
voxl_esc: cycle: 0 events, 0us elapsed, 0.00us avg, min 0us max 0us 0.000us rms
voxl_esc: output update interval: 0 events, 0.00us avg, min 0us max 0us 0.000us rms
INFO  [mixer_module] Param prefix: VOXL_ESC
control latency: 0 events, 0us elapsed, 0.00us avg, min 0us max 0us 0.000us rms
Channel Configuration:
Channel 0: func:   0, value: 0, failsafe: 0, disarmed: 0, min: 5500, max: 15000
Channel 1: func:   0, value: 0, failsafe: 0, disarmed: 0, min: 5500, max: 15000
Channel 2: func:   0, value: 0, failsafe: 0, disarmed: 0, min: 5500, max: 15000
Channel 3: func:   0, value: 0, failsafe: 0, disarmed: 0, min: 5500, max: 15000
```

## Reply by Jetson Nano · 2025-04-22 04:13:09 UTC (in reply to Eric Katzfey)

@Eric-Katzfey @Alex-Kushleyev  

Voxl2 is connected to Flight core v2 through telem 1.
ESC is connected to flight core through telem 2.
the parameters are the following

![Screenshot from 2025-04-22 09-41-07.png](https://forum.modalai.com/assets/uploads/files/1745295121437-screenshot-from-2025-04-22-09-41-07.png) 

![Screenshot from 2025-04-22 09-42-31.png](https://forum.modalai.com/assets/uploads/files/1745295169061-screenshot-from-2025-04-22-09-42-31.png)

 ![Screenshot from 2025-04-22 09-40-50.png](https://forum.modalai.com/assets/uploads/files/1745295121473-screenshot-from-2025-04-22-09-40-50.png)

## Reply by Alex Kushleyev (ModalAI staff) · 2025-04-22 14:20:54 UTC (in reply to Jetson Nano)

@Jetson-Nano said in [VOXL FPV Racing 4\-in\-1 ESC with flight core v2 and voxl2](/post/21953):
> if i start esc through voxl_esc start , it is starting

Can you please provide the debug prints that `voxl_esc` driver outputs when you call `voxl_esc start` ?

Alex

## Reply by Jetson Nano · 2025-04-22 14:24:58 UTC (in reply to Alex Kushleyev)

@Alex-Kushleyev When I run it for sometime it is makes the ESC blink once.
then once again if I run the command it gives the following statement
```Error [voxl_esc] Task already running```

## Reply by Alex Kushleyev (ModalAI staff) · 2025-04-22 14:26:26 UTC (in reply to Jetson Nano)

@Jetson-Nano , you can stop the task and run it again or just look at the console output when you power on FC V2, so you see what happens when `voxl_esc` task prints when it start for the first time.

## Reply by Jetson Nano · 2025-04-22 14:32:26 UTC (in reply to Alex Kushleyev)

@Alex-Kushleyev 
```
nsh> voxl_esc stop
ERROR [voxl_esc] timeout, forcing stop
ERROR [voxl_esc] failed restoring uart to original state
ERROR [voxl_esc] error closing uart
nsh> voxl_esc start
ERROR [px4_work_queue] wq:ttyS4 not available
ERROR [px4_work_queue] init failed
INFO  [voxl_esc] Starting VOXL ESC driver
INFO  [voxl_esc] Params: VOXL_ESC_CONFIG: 1
INFO  [voxl_esc] Params: VOXL_ESC_MODE: 0
INFO  [voxl_esc] Params: VOXL_ESC_BAUD: 250000
INFO  [voxl_esc] Params: VOXL_ESC_FUNC1: 101
INFO  [voxl_esc] Params: VOXL_ESC_FUNC2: 104
INFO  [voxl_esc] Params: VOXL_ESC_FUNC3: 102
INFO  [voxl_esc] Params: VOXL_ESC_FUNC4: 103
INFO  [voxl_esc] Params: VOXL_ESC_SDIR1: 0
INFO  [voxl_esc] Params: VOXL_ESC_SDIR2: 0
INFO  [voxl_esc] Params: VOXL_ESC_SDIR3: 0
INFO  [voxl_esc] Params: VOXL_ESC_SDIR4: 0
INFO  [voxl_esc] Params: VOXL_ESC_RPM_MIN: 5500
INFO  [voxl_esc] Params: VOXL_ESC_RPM_MAX: 15000
INFO  [voxl_esc] Params: VOXL_ESC_T_PERC: 90
INFO  [voxl_esc] Params: VOXL_ESC_T_DEAD: 20
INFO  [voxl_esc] Params: VOXL_ESC_T_EXPO: 35
INFO  [voxl_esc] Params: VOXL_ESC_T_MINF: 0.150000
INFO  [voxl_esc] Params: VOXL_ESC_T_COSP: 0.990000
INFO  [voxl_esc] Params: VOXL_ESC_VLOG: 0
INFO  [voxl_esc] Params: VOXL_ESC_PUB_BST: 1
INFO  [voxl_esc] Params: VOXL_ESC_T_WARN: 0
INFO  [voxl_esc] Params: VOXL_ESC_T_OVER: 0
INFO  [voxl_esc] Params: GPIO_CTL_CH: 0
nsh> 
```

can you verify whether it is a parameter related error. I have mentioned the parameters in the above thread.

## Reply by Alex Kushleyev (ModalAI staff) · 2025-04-22 14:39:10 UTC (in reply to Jetson Nano)

@Jetson-Nano said in [VOXL FPV Racing 4\-in\-1 ESC with flight core v2 and voxl2](/post/21960):
> ERROR [px4_work_queue] wq:ttyS4 not available

the error above seems like an issue. 

Also is your ESC actually running at 250K baud rate? Did you verify this using `voxl-esc` tools?

Additionally, it seems the `voxl_esc` driver does not produce the prints I was expecting, let me check to make sure the FC V2 is using the latest `voxl_esc` implementation.

Alex

## Reply by Jetson Nano · 2025-04-22 14:42:27 UTC (in reply to Alex Kushleyev)

@Alex-Kushleyev  
Yes it is running in the 250k baud rate. 
I did not verify with the voxl-esc tools. I directly connected it to the FC.
I am using the voxl-fpv-dev version of px4

## Reply by Alex Kushleyev (ModalAI staff) · 2025-04-22 14:43:51 UTC (in reply to Jetson Nano)

@Jetson-Nano , what do you mean `voxl-fpv-dev` version of px4? can you provide the link to the exact release?

## Reply by Jetson Nano · 2025-04-22 14:45:26 UTC (in reply to Alex Kushleyev)

@Alex-Kushleyev 
https://github.com/modalai/px4-firmware/tree/voxl-fpv-dev

## Reply by Jetson Nano · 2025-04-22 14:46:41 UTC (in reply to Alex Kushleyev)

@Alex-Kushleyev here you had mentioned a version where the change has been made with respect to the delay.
https://forum.modalai.com/post/21951

## Reply by Alex Kushleyev (ModalAI staff) · 2025-04-22 14:50:00 UTC (in reply to Jetson Nano)

@Jetson-Nano , from your above screen shot from QGC, it seems you are using TELEM2 for MAV0, so that is probably why the port is not able to open. You should probably set MAV_0_CONFIG to `Disabled`...
```
ERROR [px4_work_queue] wq:ttyS4 not available
```

## Reply by Jetson Nano · 2025-04-22 15:12:09 UTC (in reply to Alex Kushleyev)

@Alex-Kushleyev Thank you for the help . I changed the parameter and now the ESC has been initialised. motor are able to rotate.
Also is there any other parameter i should be aware of

## Reply by Alex Kushleyev (ModalAI staff) · 2025-04-22 16:27:13 UTC (in reply to Jetson Nano)

@Jetson-Nano , since you are probably using a custom motor and propeller you should:
- first of all, update the ESC firmware to the latest
- calibrate the ESC for the motor/propeller and upload params
- update min and max rpm params in PX4 because they are used to scale the control output
- set the correct motor mapping and direction in px4 params
- i also recommend updating the baud rate to at least 921600 (or 1M). We are using 2Mbit for all latest ESC configs now. This reduces latency and ensures that you don't have ESC packet drops (depending on the update rate of your flight control loop)

In order to perform the updates and tuning, you will need to use `voxl-esc` tools. Please see the following page for more info: https://docs.modalai.com/voxl-escs/faq/

Alex

## Reply by Jetson Nano · 2025-04-22 16:34:44 UTC (in reply to Alex Kushleyev)

@Alex-Kushleyev Thank you for the support. I will make the changes you have mentioned.

## Reply by Jetson Nano · 2025-06-04 20:05:32 UTC (in reply to Jetson Nano)

hey @Alex-Kushleyev 
I am facing the same issue again, the ESC is not initialising when connected through fc v2 , i have followed all the suggestions you mentioned earlier. the FC as well as VOXL 2 is powered through ESC.

```
nsh> voxl_esc start
INFO  [voxl_esc] VOXL_ESC: Starting VOXL ESC driver
INFO  [voxl_esc] Params: VOXL_ESC_CONFIG: 1
INFO  [voxl_esc] Params: VOXL_ESC_MODE: 0
INFO  [voxl_esc] Params: VOXL_ESC_BAUD: 2000000
INFO  [voxl_esc] Params: VOXL_ESC_FUNC1: 101
INFO  [voxl_esc] Params: VOXL_ESC_FUNC2: 104
INFO  [voxl_esc] Params: VOXL_ESC_FUNC3: 102
INFO  [voxl_esc] Params: VOXL_ESC_FUNC4: 103
INFO  [voxl_esc] Params: VOXL_ESC_SDIR1: 0
INFO  [voxl_esc] Params: VOXL_ESC_SDIR2: 0
INFO  [voxl_esc] Params: VOXL_ESC_SDIR3: 0
INFO  [voxl_esc] Params: VOXL_ESC_SDIR4: 0
INFO  [voxl_esc] Params: VOXL_ESC_RPM_MIN: 5500
INFO  [voxl_esc] Params: VOXL_ESC_RPM_MAX: 15000
INFO  [voxl_esc] Params: VOXL_ESC_T_PERC: 90
INFO  [voxl_esc] Params: VOXL_ESC_T_DEAD: 20
INFO  [voxl_esc] Params: VOXL_ESC_T_EXPO: 35
INFO  [voxl_esc] Params: VOXL_ESC_T_MINF: 0.150000
INFO  [voxl_esc] Params: VOXL_ESC_T_COSP: 0.990000
INFO  [voxl_esc] Params: VOXL_ESC_VLOG: 0
INFO  [voxl_esc] Params: VOXL_ESC_PUB_BST: 1
INFO  [voxl_esc] Params: VOXL_ESC_T_WARN: 0
INFO  [voxl_esc] Params: VOXL_ESC_T_OVER: 0
INFO  [voxl_esc] Params: GPIO_CTL_CH: 0
nsh> voxl_esc status
INFO  [voxl_esc] not running
nsh> voxl_esc start
INFO  [voxl_esc] VOXL_ESC: Starting VOXL ESC driver
INFO  [voxl_esc] Params: VOXL_ESC_CONFIG: 1
INFO  [voxl_esc] Params: VOXL_ESC_MODE: 0
INFO  [voxl_esc] Params: VOXL_ESC_BAUD: 2000000
INFO  [voxl_esc] Params: VOXL_ESC_FUNC1: 101
INFO  [voxl_esc] Params: VOXL_ESC_FUNC2: 104
INFO  [voxl_esc] Params: VOXL_ESC_FUNC3: 102
INFO  [voxl_esc] Params: VOXL_ESC_FUNC4: 103
INFO  [voxl_esc] Params: VOXL_ESC_SDIR1: 0
INFO  [voxl_esc] Params: VOXL_ESC_SDIR2: 0
INFO  [voxl_esc] Params: VOXL_ESC_SDIR3: 0
INFO  [voxl_esc] Params: VOXL_ESC_SDIR4: 0
INFO  [voxl_esc] Params: VOXL_ESC_RPM_MIN: 5500
INFO  [voxl_esc] Params: VOXL_ESC_RPM_MAX: 15000
INFO  [voxl_esc] Params: VOXL_ESC_T_PERC: 90
INFO  [voxl_esc] Params: VOXL_ESC_T_DEAD: 20
INFO  [voxl_esc] Params: VOXL_ESC_T_EXPO: 35
INFO  [voxl_esc] Params: VOXL_ESC_T_MINF: 0.150000
INFO  [voxl_esc] Params: VOXL_ESC_T_COSP: 0.990000
INFO  [voxl_esc] Params: VOXL_ESC_VLOG: 0
INFO  [voxl_esc] Params: VOXL_ESC_PUB_BST: 1
INFO  [voxl_esc] Params: VOXL_ESC_T_WARN: 0
INFO  [voxl_esc] Params: VOXL_ESC_T_OVER: 0
INFO  [voxl_esc] Params: GPIO_CTL_CH: 0
nsh> 
```

## Reply by Alex Kushleyev (ModalAI staff) · 2025-06-05 03:13:59 UTC (in reply to Jetson Nano)

@Jetson-Nano ,

The primary causes of ESC not being detected by the FC (aside from hardware / wiring issues) is using incorrect UART port or incorrect baud rate. So you should make sure the ESC is running the latest firmware, double check the params that you want to use on the ESC (for your motor / prop) and you can also set the ESC baud rate in the ESC params. You should set up your ESC (using `voxl-esc` tools) before plugging it into your FC, so that you know exactly what your ESC is set up to do and then you just need to match your PX4 params to what you set in the ESC (baud rate, rpm limits, and use correct UART port).

Alex

## Reply by Jetson Nano · 2025-06-05 19:37:27 UTC (in reply to Alex Kushleyev)

@Alex-Kushleyev Thank you for reverting, I didnt change anything with respect to the fc or ESC, the firmware is the same. 
could you help me with understanding why it was working earlier , it is not now.
The firmware of the FC is voxl-fpv-dev version, and when i tried to build again it is giving error, and not building.
I still dont know whether the issue is with respect to FC firmware or ESC

## Reply by Alex Kushleyev (ModalAI staff) · 2025-06-06 13:49:01 UTC (in reply to Jetson Nano)

@Jetson-Nano , please confirm the ESC is working by using a usb to serial connection directly to the esc and voxl-esc Python tools on a Linux PC or VM.

You can run simple commands to detect the esc and perform spin tests if needed, this is all documented. 

https://docs.modalai.com/voxl-escs/faq/

If the esc is ok, then you will need to double check the FC v2 setup.

Alex

## Reply by Jetson Nano · 2025-07-11 09:58:06 UTC (in reply to Alex Kushleyev)

Hey @Alex-Kushleyev , for the same setup I mentioned above my esc is not starting by default, while I run voxl_esc start in mavlink console, it starts and works. 
what could be the reason for such behaviour. Please could you help me out

## Reply by Alex Kushleyev (ModalAI staff) · 2025-07-11 17:43:00 UTC (in reply to Jetson Nano)

@Jetson-Nano , this is likely related to the fact that the FC starts quicker than the ESC bootloader's 1s wait time. We discussed this before.

So if you are saying that delaying the start of voxl_esc driver in px4 on your FC solves the problem, then the issue is exactly that.

Please delay the start of the voxl_esc driver in your px4 start-up script, for example you can see it at the bottom of the script here : https://github.com/modalai/px4-firmware/blob/bugfix-fpv-rev0-airframe/boards/modalai/fc-v2/init/rc.board_sensors

```
if param greater VOXL_ESC_CONFIG 0
then
	usleep 1500000
	voxl_esc start
fi
```

## Reply by Jetson Nano · 2025-07-12 06:33:55 UTC (in reply to Alex Kushleyev)

@Alex-Kushleyev I have already tried it, It was working fine earlier. since past 2 days the behaviour has changed, I have verified everything else and nothing else could be a reason for such behaviour , I even played around with delay to verify it, still the same issue. 
please excuse me for repeating the questions but is there any other reason that can cause this issue.

## Reply by Alex Kushleyev (ModalAI staff) · 2025-07-15 17:24:05 UTC (in reply to Jetson Nano)

@Jetson-Nano ,

Thank you for clarifying. Unfortunately, since I don't know what you changed between the working and non-working condition, it is hard to help. Also, since you are indicating that the ESC is responding if you manually start the esc driver, then the ESC itself should still be functional. 

Please try to backtrack your changes until you have a working setup again.

Alex

## Reply by Jetson Nano · 2025-07-16 04:23:32 UTC (in reply to Alex Kushleyev)

@Alex-Kushleyev , I will backtrack the steps and try re-configuring the setup.

## Reply by Jetson Nano · 2025-08-05 11:37:53 UTC (in reply to Jetson Nano)

@Alex-Kushleyev @Eric-Katzfey 
Hello guys, I am facing a new error where when I try to use Optical flow by enabling the UAVCAN in the default.px4board, since it was commented out. Whenever try to enable it and build it is giving error. I want to use CAN port on the FC v2 for Optical Flow. It would be of great help , if you could help with this or guide me.

```
FAILED: src/drivers/uavcan/CMakeFiles/drivers__uavcan.dir/uavcan_servers.cpp.obj 

/usr/bin/ccache /opt/gcc-arm-none-eabi-9-2020-q2-update/bin/arm-none-eabi-g++ -DCONFIG_ARCH_BOARD_MODALAI_FC_V2 -DMODULE_NAME=\"uavcan\" -DPX4_BOARD_LABEL=\"default\" -DPX4_BOARD_NAME=\"MODALAI_FC_V2\" -DPX4_MAIN=uavcan_app_main -DUAVCAN_CPP_VERSION=UAVCAN_CPP03 -DUAVCAN_DRIVER=uavcan_stm32h7 -DUAVCAN_IMPLEMENT_PLACEMENT_NEW=1 -DUAVCAN_MEM_POOL_BLOCK_SIZE=48 -DUAVCAN_NO_ASSERTIONS -DUAVCAN_PLATFORM=generic -DUAVCAN_STM32H7_NUM_IFACES=2 -DUAVCAN_STM32H7_NUTTX=1 -DUAVCAN_STM32H7_TIMER_NUMBER=2 -D_SYS_CDEFS_H_ -D_SYS_REENT_H_ -D__CUSTOM_FILE_IO__ -D__PX4_NUTTX -D__STDC_FORMAT_MACROS -I/home/t/p/px4-firmware/boards/modalai/fc-v2/src -I/home/t/p/px4-firmware/platforms/nuttx/src/px4/common/include -I/home/t/p/px4-firmware/build/modalai_fc-v2_default -I/home/t/p/px4-firmware/build/modalai_fc-v2_default/src/lib -I/home/t/p/px4-firmware/platforms/nuttx/src/px4/stm/stm32h7/include -I/home/t/p/px4-firmware/platforms/common -I/home/t/p/px4-firmware/platforms/common/include -I/home/t/p/px4-firmware/src -I/home/t/p/px4-firmware/src/include -I/home/t/p/px4-firmware/src/lib -I/home/t/p/px4-firmware/src/lib/matrix -I/home/t/p/px4-firmware/src/modules -I/home/t/p/px4-firmware/platforms/nuttx/NuttX/nuttx/arch/arm/src/armv7-m -I/home/t/p/px4-firmware/platforms/nuttx/NuttX/nuttx/arch/arm/src/chip -I/home/t/p/px4-firmware/platforms/nuttx/NuttX/nuttx/arch/arm/src/common -I/home/t/p/px4-firmware/platforms/nuttx/NuttX/apps/include -I/home/t/p/px4-firmware/build/modalai_fc-v2_default/uORB/topics -I/home/t/p/px4-firmware/build/modalai_fc-v2_default/external/Install/include -I/home/t/p/px4-firmware/build/modalai_fc-v2_default/src/drivers/uavcan/include/dsdlc_generated -I/home/t/p/px4-firmware/src/drivers/uavcan/libuavcan/libuavcan/include -I/home/t/p/px4-firmware/src/drivers/uavcan/libuavcan/libuavcan/include/dsdlc_generated -I/home/t/p/px4-firmware/src/drivers/uavcan/libuavcan/libuavcan_drivers/posix/include -I/home/t/p/px4-firmware/src/drivers/uavcan/uavcan_drivers/stm32h7/driver/include -isystem /home/t/p/px4-firmware/platforms/nuttx/NuttX/include/cxx -isystem /home/t/p/px4-firmware/platforms/nuttx/NuttX/nuttx/include/cxx -isystem /home/t/p/px4-firmware/platforms/nuttx/NuttX/nuttx/include -mcpu=cortex-m7 -mthumb -mfpu=fpv5-d16 -mfloat-abi=hard -Os -DNDEBUG -std=gnu++14 -g -fdata-sections -ffunction-sections -fomit-frame-pointer -fmerge-all-constants -fno-signed-zeros -fno-trapping-math -freciprocal-math -fno-math-errno -fno-strict-aliasing -fvisibility=hidden -include visibility.h -Wall -Wextra -Werror -Warray-bounds -Wcast-align -Wdisabled-optimization -Wdouble-promotion -Wfatal-errors -Wfloat-equal -Wformat-security -Winit-self -Wlogical-op -Wpointer-arith -Wshadow -Wuninitialized -Wunknown-pragmas -Wunused-variable -Wno-missing-field-initializers -Wno-missing-include-dirs -Wno-unused-parameter -fdiagnostics-color=always -Wno-stringop-truncation -fno-builtin-printf -fno-strength-reduce -Wformat=1 -Wunused-but-set-variable -Wno-format-truncation -fcheck-new -Wreorder -Wno-overloaded-virtual -fno-rtti -fno-exceptions -fno-sized-deallocation -fno-threadsafe-statics -nostdinc++ -Wno-cast-align -Wno-deprecated-copy -Wno-address-of-packed-member -Wframe-larger-than=4096 -Wno-format-security -D__KERNEL__ -MD -MT src/drivers/uavcan/CMakeFiles/drivers__uavcan.dir/uavcan_servers.cpp.obj -MF src/drivers/uavcan/CMakeFiles/drivers__uavcan.dir/uavcan_servers.cpp.obj.d -o src/drivers/uavcan/CMakeFiles/drivers__uavcan.dir/uavcan_servers.cpp.obj -c /home/t/p/px4-firmware/src/drivers/uavcan/uavcan_servers.cpp

In file included from /home/t/p/px4-firmware/src/drivers/uavcan/uavcan_servers.cpp:52:

/home/t/p/px4-firmware/src/drivers/uavcan/uavcan_main.hpp:79:10: fatal error: uORB/topics/uavcan_parameter_request.h: No such file or directory

   79 | #include <uORB/topics/uavcan_parameter_request.h>

      |          ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

compilation terminated.

[596/1151] Building CXX object src/dri...rivers__uavcan.dir/uavcan_main.cpp.obj

FAILED: src/drivers/uavcan/CMakeFiles/drivers__uavcan.dir/uavcan_main.cpp.obj 

/usr/bin/ccache /opt/gcc-arm-none-eabi-9-2020-q2-update/bin/arm-none-eabi-g++ -DCONFIG_ARCH_BOARD_MODALAI_FC_V2 -DMODULE_NAME=\"uavcan\" -DPX4_BOARD_LABEL=\"default\" -DPX4_BOARD_NAME=\"MODALAI_FC_V2\" -DPX4_MAIN=uavcan_app_main -DUAVCAN_CPP_VERSION=UAVCAN_CPP03 -DUAVCAN_DRIVER=uavcan_stm32h7 -DUAVCAN_IMPLEMENT_PLACEMENT_NEW=1 -DUAVCAN_MEM_POOL_BLOCK_SIZE=48 -DUAVCAN_NO_ASSERTIONS -DUAVCAN_PLATFORM=generic -DUAVCAN_STM32H7_NUM_IFACES=2 -DUAVCAN_STM32H7_NUTTX=1 -DUAVCAN_STM32H7_TIMER_NUMBER=2 -D_SYS_CDEFS_H_ -D_SYS_REENT_H_ -D__CUSTOM_FILE_IO__ -D__PX4_NUTTX -D__STDC_FORMAT_MACROS -I/home/t/p/px4-firmware/boards/modalai/fc-v2/src -I/home/t/p/px4-firmware/platforms/nuttx/src/px4/common/include -I/home/t/p/px4-firmware/build/modalai_fc-v2_default -I/home/t/p/px4-firmware/build/modalai_fc-v2_default/src/lib -I/home/t/p/px4-firmware/platforms/nuttx/src/px4/stm/stm32h7/include -I/home/t/p/px4-firmware/platforms/common -I/home/t/p/px4-firmware/platforms/common/include -I/home/t/p/px4-firmware/src -I/home/t/p/px4-firmware/src/include -I/home/t/p/px4-firmware/src/lib -I/home/t/p/px4-firmware/src/lib/matrix -I/home/t/p/px4-firmware/src/modules -I/home/t/p/px4-firmware/platforms/nuttx/NuttX/nuttx/arch/arm/src/armv7-m -I/home/t/p/px4-firmware/platforms/nuttx/NuttX/nuttx/arch/arm/src/chip -I/home/t/p/px4-firmware/platforms/nuttx/NuttX/nuttx/arch/arm/src/common -I/home/t/p/px4-firmware/platforms/nuttx/NuttX/apps/include -I/home/t/p/px4-firmware/build/modalai_fc-v2_default/uORB/topics -I/home/t/p/px4-firmware/build/modalai_fc-v2_default/external/Install/include -I/home/t/p/px4-firmware/build/modalai_fc-v2_default/src/drivers/uavcan/include/dsdlc_generated -I/home/t/p/px4-firmware/src/drivers/uavcan/libuavcan/libuavcan/include -I/home/t/p/px4-firmware/src/drivers/uavcan/libuavcan/libuavcan/include/dsdlc_generated -I/home/t/p/px4-firmware/src/drivers/uavcan/libuavcan/libuavcan_drivers/posix/include -I/home/t/p/px4-firmware/src/drivers/uavcan/uavcan_drivers/stm32h7/driver/include -isystem /home/t/p/px4-firmware/platforms/nuttx/NuttX/include/cxx -isystem /home/t/p/px4-firmware/platforms/nuttx/NuttX/nuttx/include/cxx -isystem /home/t/p/px4-firmware/platforms/nuttx/NuttX/nuttx/include -mcpu=cortex-m7 -mthumb -mfpu=fpv5-d16 -mfloat-abi=hard -Os -DNDEBUG -std=gnu++14 -g -fdata-sections -ffunction-sections -fomit-frame-pointer -fmerge-all-constants -fno-signed-zeros -fno-trapping-math -freciprocal-math -fno-math-errno -fno-strict-aliasing -fvisibility=hidden -include visibility.h -Wall -Wextra -Werror -Warray-bounds -Wcast-align -Wdisabled-optimization -Wdouble-promotion -Wfatal-errors -Wfloat-equal -Wformat-security -Winit-self -Wlogical-op -Wpointer-arith -Wshadow -Wuninitialized -Wunknown-pragmas -Wunused-variable -Wno-missing-field-initializers -Wno-missing-include-dirs -Wno-unused-parameter -fdiagnostics-color=always -Wno-stringop-truncation -fno-builtin-printf -fno-strength-reduce -Wformat=1 -Wunused-but-set-variable -Wno-format-truncation -fcheck-new -Wreorder -Wno-overloaded-virtual -fno-rtti -fno-exceptions -fno-sized-deallocation -fno-threadsafe-statics -nostdinc++ -Wno-cast-align -Wno-deprecated-copy -Wno-address-of-packed-member -Wframe-larger-than=4096 -Wno-format-security -D__KERNEL__ -MD -MT src/drivers/uavcan/CMakeFiles/drivers__uavcan.dir/uavcan_main.cpp.obj -MF src/drivers/uavcan/CMakeFiles/drivers__uavcan.dir/uavcan_main.cpp.obj.d -o src/drivers/uavcan/CMakeFiles/drivers__uavcan.dir/uavcan_main.cpp.obj -c /home/t/p/px4-firmware/src/drivers/uavcan/uavcan_main.cpp

In file included from /home/t/p/px4-firmware/src/drivers/uavcan/uavcan_main.cpp:63:

/home/t/p/px4-firmware/src/drivers/uavcan/uavcan_main.hpp:79:10: fatal error: uORB/topics/uavcan_parameter_request.h: No such file or directory

   79 | #include <uORB/topics/uavcan_parameter_request.h>

      |          ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

compilation terminated.

[603/1151] Building CXX object src/dri..._uavcan.dir/sensors/ice_status.cpp.obj

ninja: build stopped: subcommand failed.

make: *** [Makefile:227: modalai_fc-v2_default] Error 1
```

## Reply by Eric Katzfey (ModalAI staff) · 2025-08-05 15:10:30 UTC (in reply to Jetson Nano)

@Jetson-Nano Can you please start a new thread for this new topic?