Flash savings ideas : features/drivers to disable/remove to save flash

[rmackay9]

AP's flash size is constantly growing as new features and drivers are added but unfortunately the STM32 autopilot's CPUs flash size is not keeping up. This means we need to disable or remove lesser used features from many boards.

This issue is to collect ideas (primarily from members of the core dev team) on features/drivers they think could be sacrificed.

Note we have a few ways to reduce flash:

1. move the feature/driver to be disabled by default thus forcing users to rely on the custom build server
2. migrate the feature to Lua forcing the user to load a Lua script
3. completely remove the feature or driver

Suggestions include:

• Generator (suggested by PeterB)
• External AHRS (suggested by PeterB, Tridge)
• Avoid ADSB copter flight mode (suggested by Randy)
• AP_GPS_GSOF once we have it available as an EAHRS (from RyanF)
• KDECAN
• PiccoloCAN

[Ryanf55]

• AP_GPS_GSOF once we have it available as an EAHRS.

+1 on EAHRS

[timtuxworth]

Plane: suggesting all of these could be custom build server options only.
ICE
Precision Landing
Gimbals (except for Mount and Servo Gimbal)
VTX
Generator

[amilcarlucas]

Winch
Exotic ESCs

[peterbarker]

I've used some of these ideas in https://github.com/ArduPilot/ardupilot/pull/28226/files - thanks!

[peterbarker]

• bootloader flashing

[Hwurzburg]

• Rangefinder on Plane

[tridge]

@andyp1per suggested -Os or -O1 default on current 2M boards

[peterbarker]

disable-in-turn.csv

That's the output from ./Tools/autotest/test_build_options.py's "disable in turn" step. It shows the number of bytes saved on CubeOrange when each feature is disabled. This might help selection of things to boot from the standard build.

[rmackay9]

Thanks @peterbarker. I've extracted your list and sorted it for copter

Feature	copter
AP_SCRIPTING_ENABLED	182160
HAL_NAVEKF3_AVAILABLE	171400
HAL_ENABLE_DRONECAN_DRIVERS	96120
HAL_LOGGING_ENABLED	95704
HAL_MOUNT_ENABLED	67300
AP_FENCE_ENABLED	50360
AP_RANGEFINDER_ENABLED	48056
HAL_GYROFFT_ENABLED	42308
OSD_ENABLED	40568
AP_RCPROTOCOL_ENABLED	35888
AP_OPTICALFLOW_ENABLED	33816
AP_FILESYSTEM_ROMFS_ENABLED	32912
HAL_MSP_ENABLED	31808
AP_BOOTLOADER_FLASHING_ENABLED	31648
HAL_EXTERNAL_AHRS_ENABLED	29112
HAL_PROXIMITY_ENABLED	26824
HAL_ADSB_ENABLED	25800
AP_CAMERA_ENABLED	25192
AP_FRSKY_TELEM_ENABLED	24288
AP_AIRSPEED_ENABLED	22984
AP_FRSKY_SPORT_TELEM_ENABLED	21952
AP_OAPATHPLANNER_ENABLED	19016
HAL_WITH_MSP_DISPLAYPORT	18248
AP_FRSKY_SPORT_PASSTHROUGH_ENABLED	18240
HAL_SOLO_GIMBAL_ENABLED	17192
AP_AVOIDANCE_ENABLED	15680
HAL_EFI_ENABLED	14816
COMPASS_CAL_ENABLED	14592
AP_BEACON_ENABLED	14424
EK3_FEATURE_OPTFLOW_FUSION	12816
AP_GPS_UBLOX_ENABLED	12368
AP_RCPROTOCOL_CRSF_ENABLED	11640
OSD_PARAM_ENABLED	11596
AP_BARO_PROBE_EXTERNAL_I2C_BUSES	11296
HAL_VISUALODOM_ENABLED	10520
AP_EXTERNAL_AHRS_INERTIALLABS_ENABLED	10344
AC_PRECLAND_ENABLED	10144
AP_INERTIALSENSOR_HARMONICNOTCH_ENABLED	9824
HAL_CRSF_TELEM_ENABLED	9680
AP_VIDEOTX_ENABLED	9036
HAL_MOUNT_XACTI_ENABLED	8968
HAL_PICCOLO_CAN_ENABLE	8920
AP_RCPROTOCOL_SRXL2_ENABLED	8584
HAL_GENERATOR_ENABLED	8544
HAL_ADSB_SAGETECH_MXS_ENABLED	8376
HAL_INS_TEMPERATURE_CAL_ENABLE	8040
HAL_MOUNT_TOPOTEK_ENABLED	7092
AP_GPS_NMEA_ENABLED	6176
HAL_MOUNT_SIYI_ENABLED	5992
AP_CAMERA_RUNCAM_ENABLED	5600
AP_OPTICALFLOW_PIXART_ENABLED	5536
AP_RPM_ENABLED	5504
AP_WINCH_ENABLED	5060
GPS_MOVING_BASELINE	5040
AP_NOTIFY_TONEALARM_ENABLED	4984
EK3_FEATURE_DRAG_FUSION	4984
AP_GPS_SBF_ENABLED	4904
AP_GPS_SBP_ENABLED	4864
AP_SERVO_TELEM_ENABLED	4864
AP_EXTERNAL_AHRS_VECTORNAV_ENABLED	4816
HAL_MOUNT_VIEWPRO_ENABLED	4812
MODE_ZIGZAG_ENABLED	4784
AP_MAVLINK_FTP_ENABLED	4648
AP_CRASHDUMP_ENABLED	4636
MODE_FLOWHOLD_ENABLED	4616
HAL_SPEKTRUM_TELEM_ENABLED	4576
AP_FOLLOW_ENABLED	4448
AP_SERIALMANAGER_REGISTER_ENABLED	4448
AP_RELAY_ENABLED	4376
MODE_SYSTEMID_ENABLED	4208
AP_BATTERY_SMBUS_ENABLED	4172
HAL_DISPLAY_ENABLED	4168
AP_RANGEFINDER_VL53L1X_ENABLED	4152
AP_CAN_SLCAN_ENABLED	4096
AP_RCPROTOCOL_GHST_ENABLED	3672
HAL_WITH_FRSKY_TELEM_BIDIRECTIONAL	3496
AP_CAMERA_INFO_FROM_SCRIPT_ENABLED	3480
HAL_ADSB_UCP_ENABLED	3416
AP_FETTEC_ONEWIRE_ENABLED	3296
EK3_FEATURE_EXTERNAL_NAV	3272
AP_FILESYSTEM_PARAM_ENABLED	3208
AP_RANGEFINDER_VL53L0X_ENABLED	3200
AP_SMARTAUDIO_ENABLED	3144
AP_GPS_BLENDED_ENABLED	3096
AP_INERTIALSENSOR_FAST_SAMPLE_WINDOW_ENABLED	2968
HAL_MSP_OPTICALFLOW_ENABLED	2952
AP_COMPASS_DRONECAN_ENABLED	2872
HAL_MSP_RANGEFINDER_ENABLED	2864
HAL_RALLY_ENABLED	2848
AP_DRONECAN_SERIAL_ENABLED	2800
AP_DRONECAN_HOBBYWING_ESC_SUPPORT	2792
AP_COMPASS_BMM350_ENABLED	2656
AP_FILESYSTEM_SYS_ENABLED	2576
HAL_ADSB_SAGETECH_ENABLED	2464
AP_AIRSPEED_DRONECAN_ENABLED	2456
AP_WINCH_DAIWA_ENABLED	2452
AP_COMPASS_HMC5843_ENABLED	2448
AP_GENERATOR_IE_2400_ENABLED	2392
AP_GPS_SBP2_ENABLED	2376
AP_DRONECAN_SEND_GPS	2352
AP_EXTERNAL_AHRS_MICROSTRAIN7_ENABLED	2336
AP_RANGEFINDER_LWI2C_ENABLED	2320
AP_GHST_TELEM_ENABLED	2304
MODE_FOLLOW_ENABLED	2296
HAL_MSP_SENSORS_ENABLED	2288
AP_BARO_MSP_ENABLED	2280
AP_BATTERY_INA2XX_ENABLED	2280
AP_COMPASS_MSP_ENABLED	2280
HAL_MSP_GPS_ENABLED	2280
AP_AIRSPEED_MSP_ENABLED	2272
AP_AIRSPEED_SDP3X_ENABLED	2248
AP_GENERATOR_RICHENPOWER_ENABLED	2248
AP_FILESYSTEM_MISSION_ENABLED	2200
AP_GPS_GSOF_ENABLED	2184
AP_COMPASS_LIS3MDL_ENABLED	2128
AP_FILTER_ENABLED	2128
AP_COMPASS_MMC3416_ENABLED	2112
AP_MISSION_NAV_PAYLOAD_PLACE_ENABLED	2096
AP_BARO_DRONECAN_ENABLED	2080
AP_INERTIALSENSOR_BATCHSAMPLER_ENABLED	2072
AP_GRIPPER_ENABLED	2068
AP_VOLZ_ENABLED	2048
AC_PAYLOAD_PLACE_ENABLED	2032
AP_PROXIMITY_DRONECAN_ENABLED	2024
HAL_HIGH_LATENCY2_ENABLED	2024
AP_GPS_NMEA_UNICORE_ENABLED	2000
HAL_BUTTON_ENABLED	1984
AP_COMPASS_CALIBRATION_FIXED_YAW_ENABLED	1976
AP_EFI_SERIAL_MS_ENABLED	1936
MODE_TURTLE_ENABLED	1896
AP_ROBOTISSERVO_ENABLED	1872
HAL_PARACHUTE_ENABLED	1824
AP_PROXIMITY_LIGHTWARE_SF40C_ENABLED	1816
AP_PROXIMITY_MAV_ENABLED	1800
AP_PROXIMITY_LIGHTWARE_SF45B_ENABLED	1760
AP_EFI_DRONECAN_ENABLED	1752
AP_EXTERNAL_AHRS_MICROSTRAIN5_ENABLED	1736
AP_RSSI_ENABLED	1728
AP_SERVORELAYEVENTS_ENABLED	1712
AP_EFI_SERIAL_HIRTH_ENABLED	1688
HAL_MOUNT_SERVO_ENABLED	1688
HAL_NMEA_OUTPUT_ENABLED	1688
AP_EFI_CURRAWONG_ECU_ENABLED	1672
AP_COMPASS_IST8310_ENABLED	1656
AP_BARO_BMP085_ENABLED	1648
AP_AIRSPEED_MS4525_ENABLED	1640
AP_RANGEFINDER_WASP_ENABLED	1640
AP_AIRSPEED_MS5525_ENABLED	1600
AP_TRAMP_ENABLED	1600
AP_BARO_DPS280_ENABLED	1592
AP_BARO_SPL06_ENABLED	1592
AP_COMPASS_BMM150_ENABLED	1592
AP_COMPASS_RM3100_ENABLED	1560
AP_TEMPERATURE_SENSOR_ENABLED	1560
HAL_MOUNT_GREMSY_ENABLED	1560
AP_RPM_PIN_ENABLED	1552
AP_AIRSPEED_AUAV_ENABLED	1544
AP_CAMERA_MAVLINKCAMV2_ENABLED	1512
AP_GPS_NOVA_ENABLED	1512
AP_PROXIMITY_RPLIDARA2_ENABLED	1504
AP_GPS_ERB_ENABLED	1480
AP_SDCARD_STORAGE_ENABLED	1480
AP_RANGEFINDER_BENEWAKE_TFMINIPLUS_ENABLED	1472
HAL_MOUNT_ALEXMOS_ENABLED	1464
AP_RC_CHANNEL_AUX_FUNCTION_STRINGS_ENABLED	1456
AP_COMPASS_IST8308_ENABLED	1416
AP_BARO_FBM320_ENABLED	1392
AP_MOTORS_FRAME_QUAD_ENABLED	1376
AP_LANDINGGEAR_ENABLED	1360
AP_RANGEFINDER_DRONECAN_ENABLED	1360
AP_SCRIPTING_SERIALDEVICE_ENABLED	1352
AP_DRONECAN_HIMARK_SERVO_SUPPORT	1344
AP_TEMPCALIBRATION_ENABLED	1328
AP_BARO_BMP388_ENABLED	1320
AP_MOTORS_FRAME_OCTA_ENABLED	1312
AP_BARO_BMP280_ENABLED	1304
AP_COMPASS_QMC5883L_ENABLED	1304
MODE_FLIP_ENABLED	1296
AP_KDECAN_ENABLED	1248
AP_CUSTOMROTATIONS_ENABLED	1232
HAL_SPRAYER_ENABLED	1224
AP_OPTICALFLOW_HEREFLOW_ENABLED	1160
HAL_MOUNT_STORM32SERIAL_ENABLED	1148
AP_FRSKY_D_TELEM_ENABLED	1136
HAL_CRSF_TELEM_TEXT_SELECTION_ENABLED	1120
AC_PRECLAND_IRLOCK_ENABLED	1112
AP_AIS_ENABLED	1048
AP_BARO_LPS2XH_ENABLED	1040
AP_RANGEFINDER_PULSEDLIGHTLRF_ENABLED	1024
AP_RANGEFINDER_JRE_SERIAL_ENABLED	1008
AP_PROXIMITY_TERARANGERTOWEREVO_ENABLED	992
AP_RPM_DRONECAN_ENABLED	984
HAL_ADSB_UAVIONIX_MAVLINK_ENABLED	984
AP_AIRSPEED_DLVR_ENABLED	976
AP_GPS_SIRF_ENABLED	968
AP_RANGEFINDER_TRI2C_ENABLED	968
HAL_PLUSCODE_ENABLE	944
AP_EXTENDED_ESC_TELEM_ENABLED	936
AP_PROXIMITY_CYGBOT_ENABLED	936
AP_RANGEFINDER_BLPING_ENABLED	936
AP_RANGEFINDER_NMEA_ENABLED	928
AP_MOTORS_FRAME_OCTAQUAD_ENABLED	896
AP_CAMERA_SOLOGIMBAL_ENABLED	888
AP_RCPROTOCOL_SRXL_ENABLED	888
AP_CAMERA_MOUNT_ENABLED	872
HAL_MOUNT_CADDX_ENABLED	872
AP_AIRSPEED_ASP5033_ENABLED	856
HAL_OSD_SIDEBAR_ENABLE	848
AP_RANGEFINDER_LIGHTWARE_SERIAL_ENABLED	832
AP_NOTIFY_MAVLINK_LED_CONTROL_SUPPORT_ENABLED	824
AP_RANGEFINDER_TOFSENSEF_I2C_ENABLED	824
HAL_MOUNT_STORM32MAVLINK_ENABLED	824
AP_EFI_NWPWU_ENABLED	816
AP_MAVLINK_MSG_DEVICE_OP_ENABLED	816
AP_OPTICALFLOW_PX4FLOW_ENABLED	808
AP_RANGEFINDER_PWM_ENABLED	800
AP_BARO_EXTERNALAHRS_ENABLED	792
AP_PROXIMITY_RANGEFINDER_ENABLED	792
AP_RANGEFINDER_LEDDARVU8_ENABLED	776
AP_MAVLINK_MSG_SERIAL_CONTROL_ENABLED	760
AP_NOTIFY_NCP5623_ENABLED	760
AP_OPTICALFLOW_CXOF_ENABLED	760
AP_RANGEFINDER_RDS02UF_ENABLED	760
AP_CAMERA_SEND_FOV_STATUS_ENABLED	752
AP_BARO_BMP581_ENABLED	736
AP_OPTICALFLOW_UPFLOW_ENABLED	728
AP_MAVLINK_MSG_FLIGHT_INFORMATION_ENABLED	720
AP_EFI_SERIAL_LUTAN_ENABLED	704
AP_GPS_MAV_ENABLED	704
AP_MOTORS_FRAME_Y6_ENABLED	704
AP_RCPROTOCOL_ST24_ENABLED	704
AP_BATTERY_FUELFLOW_ENABLED	696
MODE_BRAKE_ENABLED	688
AP_RANGEFINDER_MAXSONARI2CXL_ENABLED	680
HAL_BARO_WIND_COMP_ENABLED	680
AP_BATTERY_FUELLEVEL_ANALOG_ENABLED	672
AP_BATTERY_SUM_ENABLED	672
AP_MOTORS_FRAME_HEXA_ENABLED	672
AP_RANGEFINDER_LEDDARONE_ENABLED	672
AP_PROXIMITY_TERARANGERTOWER_ENABLED	656
AP_RANGEFINDER_USD1_SERIAL_ENABLED	640
AP_RCPROTOCOL_SUMD_ENABLED	608
HAL_TORQEEDO_ENABLED	608
AP_CAMERA_SERVO_ENABLED	600
AP_COMPASS_EXTERNALAHRS_ENABLED	584
AP_RCPROTOCOL_SBUS_ENABLED	584
AP_WINCH_PWM_ENABLED	560
AP_OPTICALFLOW_MAV_ENABLED	544
AP_RANGEFINDER_HC_SR04_ENABLED	504
COMPASS_LEARN_ENABLED	504
AP_RANGEFINDER_MAVLINK_ENABLED	488
AP_RANGEFINDER_ANALOG_ENABLED	480
AP_ADVANCEDFAILSAFE_ENABLED	472
AP_COPTER_AHRS_AUTO_TRIM_ENABLED	472
AP_SBUSOUTPUT_ENABLED	472
AP_GENERATOR_IE_650_800_ENABLED	464
AP_MAVLINK_MSG_MISSION_REQUEST_ENABLED	448
AP_RANGEFINDER_TERARANGER_SERIAL_ENABLED	448
AP_RANGEFINDER_NOOPLOOP_ENABLED	432
AP_RCPROTOCOL_IBUS_ENABLED	432
AP_CAN_LOGGING_ENABLED	416
AP_BATTERY_FUELLEVEL_PWM_ENABLED	392
AP_BATTERY_SYNTHETIC_CURRENT_ENABLED	392
AP_RANGEFINDER_GYUS42V2_ENABLED	384
AP_RANGEFINDER_LANBAO_ENABLED	384
AP_MAVLINK_MSG_RELAY_STATUS_ENABLED	376
AP_RCPROTOCOL_MAVLINK_RADIO_ENABLED	368
AP_RANGEFINDER_LUA_ENABLED	352
AP_CAMERA_MAVLINK_ENABLED	344
AP_MOTORS_FRAME_DODECAHEXA_ENABLED	344
AP_RANGEFINDER_MAXBOTIX_SERIAL_ENABLED	344
AC_PRECLAND_COMPANION_ENABLED	312
AP_EFI_MAV_ENABLED	312
AP_CAMERA_RELAY_ENABLED	296
AP_MOTORS_FRAME_DECA_ENABLED	296
AP_FILESYSTEM_FORMAT_ENABLED	272
AP_NOTIFY_NEOPIXEL_ENABLED	264
AP_RANGEFINDER_BENEWAKE_CAN_ENABLED	264
AP_RANGEFINDER_TOFSENSEP_CAN_ENABLED	256
AP_AIRSPEED_ANALOG_ENABLED	248
AP_MAVLINK_SERVO_RELAY_ENABLED	248
AP_INERTIALSENSOR_KILL_IMU_ENABLED	240
MODE_GUIDED_NOGPS_ENABLED	240
AP_NOTIFY_PROFILED_ENABLED	216
AP_MAVLINK_MSG_RC_CHANNELS_RAW_ENABLED	208
AP_RANGEFINDER_USD1_CAN_ENABLED	208
AP_RCPROTOCOL_PPMSUM_ENABLED	208
AP_CAMERA_SEND_THERMAL_RANGE_ENABLED	176
AP_RPM_HARMONICNOTCH_ENABLED	176
AP_ICENGINE_ENABLED	144
AP_RANGEFINDER_BENEWAKE_TF02_ENABLED	144
AP_MAVLINK_MSG_VIDEO_STREAM_INFORMATION_ENABLED	136
AP_RANGEFINDER_BENEWAKE_TF03_ENABLED	136
AP_RANGEFINDER_BENEWAKE_TFMINI_ENABLED	136
AP_RPM_EFI_ENABLED	128
AP_RPM_GENERATOR_ENABLED	128
AP_RPM_ESC_TELEM_ENABLED	120
HAL_LANDING_DEEPSTALL_ENABLED	120
AP_NOTIFY_MAVLINK_PLAY_TUNE_SUPPORT_ENABLED	88
AP_BATTERY_WATT_MAX_ENABLED	8
AP_BARO_KELLERLD_ENABLED	-16
AP_BARO_THST_COMP_ENABLED	-16
AP_BATTERY_INA3221_ENABLED	-16
AP_COMPASS_IIS2MDC_ENABLED	-16
AP_COMPASS_LSM9DS1_ENABLED	-16
AP_COMPASS_MAG3110_ENABLED	-16
AP_IBUS_TELEM_ENABLED	-16
AP_LTM_TELEM_ENABLED	-16
AP_MAVLINK_MAV_CMD_REQUEST_AUTOPILOT_CAPABILITIES_ENABLED	-16
AP_NOTIFY_PROFILED_SPI_ENABLED	-16
AP_OPENDRONEID_ENABLED	-16
AP_QUICKTUNE_ENABLED	-16
AP_RANGEFINDER_HEXSOONRADAR_ENABLED	-16
AP_RANGEFINDER_NRA24_CAN_ENABLED	-16
AP_TUNING_ENABLED	-16
HAL_HOTT_TELEM_ENABLED	-16
HAL_MOUNT_XFROBOT_ENABLED	-16
HAL_SOARING_ENABLED	-16
MODE_AUTOLAND_ENABLED	-16
MODE_SPORT_ENABLED	-16
QAUTOTUNE_ENABLED	-16
AP_BATTERY_ESC_TELEM_OUTBOUND_ENABLED	-24
AP_COMPASS_DRONECAN_HIRES_ENABLED	-24
AP_COMPASS_MMC5XX3_ENABLED	-24
AP_COPTER_ADVANCED_FAILSAFE_ENABLED	-24
AP_MAVLINK_AUTOPILOT_VERSION_REQUEST_ENABLED	-24
AP_NETWORKING_BACKEND_PPP	-24
AP_OPTICALFLOW_ONBOARD_ENABLED	-24
AP_PLANE_BLACKBOX_LOGGING	-24
AP_PLANE_GLIDER_PULLUP_ENABLED	-24
AP_PLANE_SYSTEMID_ENABLED	-24
AP_PROXIMITY_HEXSOONRADAR_ENABLED	-24
AP_PROXIMITY_MR72_ENABLED	-24
AP_ROVER_ADVANCED_FAILSAFE_ENABLED	-24
AP_SERIALMANAGER_IMUOUT_ENABLED	-24
AP_TEMPERATURE_SENSOR_MCP9600_ENABLED	-24
AP_TEMPERATURE_SENSOR_SHT3X_ENABLED	-24
AP_TEMPERATURE_SENSOR_TSYS01_ENABLED	-24
AP_TEMPERATURE_SENSOR_TSYS03_ENABLED	-24
FORCE_APJ_DEFAULT_PARAMETERS	-24
HAL_NAVEKF2_AVAILABLE	-24
AC_POLYFENCE_FENCE_POINT_PROTOCOL_SUPPORT	-32
AP_DRONECAN_VOLZ_FEEDBACK_ENABLED	-32
AP_MAVLINK_MAV_CMD_SET_HAGL_ENABLED	-32
AP_MAVLINK_RALLY_POINT_PROTOCOL_ENABLED	-32
AP_OSD_LINK_STATS_EXTENSIONS_ENABLED	-32
AP_PLANE_OFFBOARD_GUIDED_SLEW_ENABLED	-32
AP_TEMPERATURE_SENSOR_MLX90614_ENABLED	-32
HAL_PERIPH_SUPPORT_LONG_CAN_PRINTF	-32
HAL_QUADPLANE_ENABLED	-32
AP_AIRSPEED_NMEA_ENABLED	-56

[amilcarlucas]

It would be great if this information would find it's way into custom.ardupilot.org
The users would be able to get a feeling for how "expensive" each function is.

[timtuxworth]

How much flash could we save by moving English language text messages (mostly sendtext) out to the GCS? I asked Co-Pilot

Great question! Replacing long English text messages with short codes (like 3-character alphanumeric identifiers) can save significant flash space in embedded firmware like ArduPilot.

There seem to be around 3000 send_text messages so the savings might be as much as 30-40k and as a bonus the GCS would be able to display messages in different languages.

[Hwurzburg]

@timtuxworth not a good ideef....that would effectively disable them in OpenTX/EdgeTX and OSDs of all kinds....and trying to keep all GCS up to date would be impossible,especially on critical items...

[Hwurzburg]

disable-in-turn.pdf
I was going to add this to the wiki, so I converted all NEGATIVEs to -na- but there are many that show as na across the boared..
@peterbarker whats the explaination?