Pixhawk 6c mini with PWM wiring of lite lidar

Pixhawk
1

Pixhawk:
pixhawk 6c mini

PX4 Autopilot Version:
v 1.15.2

Parameter setting for master and stable version :

SENS_EN_LL40LS : PWM

when flashing the build px4_fmu-v6c_default on my Pixhawk 6c mini, the problem appear similar as link below.

i changed default.px4board file to add “CONFIG_DRIVERS_PWM_INPUT=y”
and add ro distance_sensor/Kconfig “select DRIVERS_DISTANCE_SENSOR_LL40LS_PWM”
but when i build the px4_fmu-v6c_default, the error occurs like below and the board configuration of 6c’s PWMIN_TIMER_CHANNEL is 3.

#define PWMIN_TIMER_CHANNEL /* T4C3 */ 3

[637/1238] Building CXX object src/dri…ivers__pwm_input.dir/pwm_input.cpp.obj
FAILED: src/drivers/pwm_input/CMakeFiles/drivers__pwm_input.dir/pwm_input.cpp.obj
/opt/gcc-arm-none-eabi-9-2020-q2-update/bin/arm-none-eabi-g++ -DCONFIG_ARCH_BOARD_PX4_FMU_V6C -DMODULE_NAME="pwm_input" -DPX4_MAIN=pwm_input_app_main -D_SYS_CDEFS_H_ -D_SYS_REENT_H_ -D__CUSTOM_FILE_IO__ -D__PX4_NUTTX -D__STDC_FORMAT_MACROS -I/home/dcasl_kari/PX4-Autopilot/boards/px4/fmu-v6c/src -I/home/dcasl_kari/PX4-Autopilot/platforms/nuttx/src/px4/common/include -I/home/dcasl_kari/PX4-Autopilot/build/px4_fmu-v6c_default -I/home/dcasl_kari/PX4-Autopilot/build/px4_fmu-v6c_default/src/lib -I/home/dcasl_kari/PX4-Autopilot/platforms/nuttx/src/px4/stm/stm32h7/include -I/home/dcasl_kari/PX4-Autopilot/platforms/common -I/home/dcasl_kari/PX4-Autopilot/platforms/common/include -I/home/dcasl_kari/PX4-Autopilot/src -I/home/dcasl_kari/PX4-Autopilot/src/include -I/home/dcasl_kari/PX4-Autopilot/src/lib -I/home/dcasl_kari/PX4-Autopilot/src/lib/matrix -I/home/dcasl_kari/PX4-Autopilot/src/modules -I/home/dcasl_kari/PX4-Autopilot/platforms/nuttx/NuttX/nuttx/arch/arm/src/armv7-m -I/home/dcasl_kari/PX4-Autopilot/platforms/nuttx/NuttX/nuttx/arch/arm/src/chip -I/home/dcasl_kari/PX4-Autopilot/platforms/nuttx/NuttX/nuttx/arch/arm/src/common -I/home/dcasl_kari/PX4-Autopilot/platforms/nuttx/NuttX/apps/include -I/home/dcasl_kari/PX4-Autopilot/build/px4_fmu-v6c_default/external/Install/include -isystem /home/dcasl_kari/PX4-Autopilot/platforms/nuttx/NuttX/include/cxx -isystem /home/dcasl_kari/PX4-Autopilot/platforms/nuttx/NuttX/nuttx/include/cxx -isystem /home/dcasl_kari/PX4-Autopilot/platforms/nuttx/NuttX/nuttx/include -mcpu=cortex-m7 -mthumb -mfpu=fpv5-d16 -mfloat-abi=hard -Os -DNDEBUG -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++ -Wframe-larger-than=2048 -Wno-pmf-conversions -Wno-cast-align -std=gnu++14 -MD -MT src/drivers/pwm_input/CMakeFiles/drivers__pwm_input.dir/pwm_input.cpp.obj -MF src/drivers/pwm_input/CMakeFiles/drivers__pwm_input.dir/pwm_input.cpp.obj.d -o src/drivers/pwm_input/CMakeFiles/drivers__pwm_input.dir/pwm_input.cpp.obj -c /home/dcasl_kari/PX4-Autopilot/src/drivers/pwm_input/pwm_input.cpp
In file included from /home/dcasl_kari/PX4-Autopilot/src/drivers/pwm_input/pwm_input.cpp:34:
/home/dcasl_kari/PX4-Autopilot/src/drivers/pwm_input/pwm_input.h:120:2: error: #error PWMIN_TIMER_CHANNEL must be either 1 and 2.
120 | #error PWMIN_TIMER_CHANNEL must be either 1 and 2.
| ^~~~~
compilation terminated due to -Wfatal-errors.
[650/1238] Building CXX object src/dri…Files/drivers__px4io.dir/px4io.cpp.obj
ninja: build stopped: subcommand failed.
make: *** [Makefile:227: px4_fmu-v6c_default] Error 1

2

Hey since helping on that git issue, I’ve learnt a lot more about best practices for building px4 firmware. I recommend now instead of changing the config/kconfig files manually to instead build with the boardguiconfig flag at the end i.e. make px4_fmu-v6c boardguiconfig, just to remove the chance of human error.

The 6c firmware seems to be the only one that has the PWM_TIMER_CHANNEL variable set to 3. you might be able to mess around with this, but its going to be tricky work.

When i compare the pixhawk 6c page with the original pixhawk 1 page, it doesn’t mention anywhere that it supports pwm IN. I also remember reading somewhere that “some models of flight controllers didn’t support pwm IN unlike older models”. This would also explain why I was never able to get my cuav x7+ pro to work with the pwm lidarlite, as they expect in both cases for people to use the included CAN / I2C ports instead. But then again the person I was talking with in that chat was able to make it work, so maybe this means nothing.

3

thank you for your apply, we also consider about using I2C. but the manual page introduce about the PWM one. So i was curious about 6C series can use PWM.
I think I should use I2C too.