PX4 自动驾驶用户指南 (v1.13)

# 模块参考：驱动

子分类

# adc

Source: drivers/adc/board_adc (opens new window)

# 描述

ADC 驱动。

# 用法

adc <command> [arguments...]
 Commands:
   start

   test

   stop

   status        打印状态信息

# ads1115

Source: drivers/adc/ads1115 (opens new window)

# 用法

ads1115 <command> [arguments...]
 Commands:
   start
     [-I]        内部I2C总线(们)
     [-X]        外部I2C 总线(们)
     [-b <val>]  指定板总线(default=all) (外部SPI: n条总线
                 (default=1))
     [-f <val>]  总线频率单位kHz
     [-q]       安静启动 (没有设备发现时不输出消息)
     [-a <val>]  I2C 地址
                 默认: 72

   stop

   status        打印状态信息

# atxxxx

Source: drivers/osd/atxxxx (opens new window)

# 描述

例如挂载在OmnibusF4SD板上的针对 ATXXXX 芯片的OSD驱动。

可以通过 OSD_ATXXXX_CFG 参数使能.

# 用法

atxxxx <command> [arguments...]
 Commands:
   start
     [-s]        内部 SPI 总线(们)
     [-S]        外部SPI 总线(们)
     [-b <val>]  指定板总线 (默认=all) (外部 SPI: n 条总线
                 (默认=1))
     [-c <val>]  片选引脚 (对于内部SPI) 或者索引(对于外部SPI)
     [-m <val>]  SPI 模式
     [-f <val>]  总线频率单位kHz
     [-q]        安静启动 (没有发现设备时无消息输出)

   stop

   status        打印状态信息

# batmon

Source: drivers/smart_battery/batmon (opens new window)

# 描述

用于智能电池的BQ40Z50电量统计芯片

# 示例

To start at address 0x0B, on bus 4

batt_smbus -X write_flash 19069 2 27 0

# 描述

batmon <command> [arguments...]
 Commands:
   start
     [-I]        Internal I2C bus(es)
     [-X]        External I2C bus(es)
     [-b <val>]  board-specific bus (default=all) (external SPI: n-th bus
                 (default=1))
     [-f <val>]  bus frequency in kHz
     [-q]        quiet startup (no message if no device found)
     [-a <val>]  I2C address
                 default: 11

   man_info      Prints manufacturer info.

   unseal        解锁设备的flash来使能 write_flash 命令

   seal          锁住设备的flash来失能 write_flash 命令.

   suspend       从调度循环中挂起该设备

# batt_smbus

Source: drivers/batt_smbus (opens new window)

# 用法

This will enable capturing on the 4th pin. Then do:

# 用法

To write to flash to set parameters. address, number_of_bytes, byte0, ... , byteN

batt_smbus -X write_flash 19069 2 27 0

# 描述

batt_smbus <command> [arguments...]
 Commands:
   start
     [-I]        Internal I2C bus(es)
     [-X]        External I2C bus(es)
     [-b <val>]  board-specific bus (default=all) (external SPI: n-th bus
                 (default=1))
     [-f <val>]  bus frequency in kHz
     [-q]        quiet startup (no message if no device found)
     [-a <val>]  I2C address
                 default: 11

   man_info      Prints manufacturer info.

   unseal        Unseals the devices flash memory to enable write_flash
                 commands.

   seal          Seals the devices flash memory to disbale write_flash commands.

   suspend       Suspends the driver from rescheduling the cycle.

   resume        Resumes the driver from suspension.

   write_flash   Writes to flash. The device must first be unsealed with the
                 unseal command.
     [address]   The address to start writing.
     [number of bytes] Number of bytes to send.
     [data[0]...data[n]] One byte of data at a time separated by spaces.

   stop

   status        print status info

# bst

Source: drivers/telemetry/bst (opens new window)

# 示例

bst <command> [arguments...]
 Commands:
   start
     [-I]        Internal I2C bus(es)
     [-X]        External I2C bus(es)
     [-b <val>]  board-specific bus (default=all) (external SPI: n-th bus
                 (default=1))
     [-f <val>]  bus frequency in kHz
     [-q]        quiet startup (no message if no device found)
     [-a <val>]  I2C address
                 default: 118

   stop

   status        print status info

# sf1xx

Source: drivers/dshot (opens new window)

# 用法

This is the DShot output driver. It is similar to the fmu driver, and can be used as drop-in replacement to use DShot as ESC communication protocol instead of PWM.

On startup, the module tries to occupy all available pins for DShot output. It skips all pins already in use (e.g. by a camera trigger module).

It supports:

  • DShot150, DShot300, DShot600, DShot1200
  • 通过独立的串口遥控，并且发布esc_status消息
  • 通过命令行接口发送 DShot 命令

# 描述

Permanently reverse motor 1:

dshot reverse -m 1
dshot save -m 1

After saving, the reversed direction will be regarded as the normal one. So to reverse again repeat the same commands.

# 描述

dshot <command> [arguments...]
 mc_att_control <command> [arguments...]
 Commands:
   start

   stop

   status        打印状态信息

# fmu mode_pwm

Source: examples/fake_gps (opens new window)

# 描述

# 描述

fake_gps <command> [arguments...]
 mc_att_control <command> [arguments...]
 Commands:
   start

   stop

   status        打印状态信息

# fake_imu

Source: examples/fake_imu (opens new window)

# 描述

# 实现

fake_imu <command> [arguments...]
 Commands:
   start

   stop

   status        print status info

# gps

Source: examples/fake_magnetometer (opens new window)

# 示例

Publish the earth magnetic field as a fake magnetometer (sensor_mag). Requires vehicle_attitude and vehicle_gps_position.

# 用法

fake_magnetometer <command> [arguments...]
 Commands:
   start

   stop

   status        print status info

# gimbal

Source: modules/gimbal (opens new window)

# 描述

Mount/gimbal Gimbal control driver. It maps several different input methods (eg. RC or MAVLink) to a configured output (eg. AUX channels or MAVLink).

Documentation how to use it is on the gimbal_control (opens new window) page.

# Examples

Test the output by setting a angles (all omitted axes are set to 0):

gimbal test pitch -45 yaw 30

# Usage

gimbal <command> [arguments...]
 Commands:
   start

   test          Test the output: set a fixed angle for one or multiple axes
                 (gimbal must be running)
     roll|pitch|yaw <angle> Specify an axis and an angle in degrees

   stop

   status        print status info

# gps

Source: drivers/gps (opens new window)

# Description

GPS driver module that handles the communication with the device and publishes the position via uORB. It supports multiple protocols (device vendors) and by default automatically selects the correct one.

The module supports a secondary GPS device, specified via -e parameter. The position will be published on the second uORB topic instance, but it's currently not used by the rest of the system (however the data will be logged, so that it can be used for comparisons).

# Implementation

There is a thread for each device polling for data. The GPS protocol classes are implemented with callbacks so that they can be used in other projects as well (eg. QGroundControl uses them too).

# Examples

Starting 2 GPS devices (the main GPS on /dev/ttyS3 and the secondary on /dev/ttyS4):

gps start -d /dev/ttyS3 -e /dev/ttyS4

Initiate warm restart of GPS device

gps reset warm

# Usage

gps <command> [arguments...]
 Commands:
   start
     [-d <val>]  GPS device
                 values: <file:dev>, default: /dev/ttyS3
     [-b <val>]  Baudrate (can also be p:<param_name>)
                 default: 0
     [-e <val>]  Optional secondary GPS device
                 values: <file:dev>
     [-g <val>]  Baudrate (secondary GPS, can also be p:<param_name>)
                 default: 0
     [-i <val>]  GPS interface
                 values: spi|uart, default: uart
     [-j <val>]  secondary GPS interface
                 values: spi|uart, default: uart
     [-p <val>]  GPS Protocol (default=auto select)
                 values: ubx|mtk|ash|eml|fem|nmea

   stop

   status        print status info

   reset         Reset GPS device
     cold|warm|hot Specify reset type

# ina226

Source: drivers/power_monitor/ina226 (opens new window)

# Description

Driver for the INA226 power monitor.

Multiple instances of this driver can run simultaneously, if each instance has a separate bus OR I2C address.

For example, one instance can run on Bus 2, address 0x41, and one can run on Bus 2, address 0x43.

If the INA226 module is not powered, then by default, initialization of the driver will fail. To change this, use the -f flag. If this flag is set, then if initialization fails, the driver will keep trying to initialize again every 0.5 seconds. With this flag set, you can plug in a battery after the driver starts, and it will work. Without this flag set, the battery must be plugged in before starting the driver.

# Usage

ina226 <command> [arguments...]
 Commands:
   start
     [-I]        Internal I2C bus(es)
     [-X]        External I2C bus(es)
     [-b <val>]  board-specific bus (default=all) (external SPI: n-th bus
                 (default=1))
     [-f <val>]  bus frequency in kHz
     [-q]        quiet startup (no message if no device found)
     [-a <val>]  I2C address
                 default: 65
     [-k]        if initialization (probing) fails, keep retrying periodically
     [-t <val>]  battery index for calibration values (1 or 2)
                 default: 1

   stop

   status        print status info

# ina228

Source: drivers/power_monitor/ina228 (opens new window)

# Description

Driver for the INA228 power monitor.

Multiple instances of this driver can run simultaneously, if each instance has a separate bus OR I2C address.

For example, one instance can run on Bus 2, address 0x45, and one can run on Bus 2, address 0x45.

If the INA228 module is not powered, then by default, initialization of the driver will fail. To change this, use the -f flag. If this flag is set, then if initialization fails, the driver will keep trying to initialize again every 0.5 seconds. With this flag set, you can plug in a battery after the driver starts, and it will work. Without this flag set, the battery must be plugged in before starting the driver.

# Usage

ina228 <command> [arguments...]
 Commands:
   start
     [-I]        Internal I2C bus(es)
     [-X]        External I2C bus(es)
     [-b <val>]  board-specific bus (default=all) (external SPI: n-th bus
                 (default=1))
     [-f <val>]  bus frequency in kHz
     [-q]        quiet startup (no message if no device found)
     [-a <val>]  I2C address
                 default: 69
     [-k]        if initialization (probing) fails, keep retrying periodically
     [-t <val>]  battery index for calibration values (1 or 2)
                 default: 1

   stop

   status        print status info

# ina238

Source: drivers/power_monitor/ina238 (opens new window)

# Description

Driver for the INA238 power monitor.

Multiple instances of this driver can run simultaneously, if each instance has a separate bus OR I2C address.

For example, one instance can run on Bus 2, address 0x45, and one can run on Bus 2, address 0x45.

If the INA238 module is not powered, then by default, initialization of the driver will fail. To change this, use the -f flag. If this flag is set, then if initialization fails, the driver will keep trying to initialize again every 0.5 seconds. With this flag set, you can plug in a battery after the driver starts, and it will work. Without this flag set, the battery must be plugged in before starting the driver.

# 描述

ina238 <command> [arguments...]
 Commands:
   start
     [-I]        Internal I2C bus(es)
     [-X]        External I2C bus(es)
     [-b <val>]  board-specific bus (default=all) (external SPI: n-th bus
                 (default=1))
     [-f <val>]  bus frequency in kHz
     [-q]        quiet startup (no message if no device found)
     [-a <val>]  I2C address
                 default: 69
     [-k]        if initialization (probing) fails, keep retrying periodically
     [-t <val>]  battery index for calibration values (1 or 2)
                 default: 1

   stop

   status        print status info

# iridiumsbd

Source: drivers/telemetry/iridiumsbd (opens new window)

# 实现

IridiumSBD driver.

Creates a virtual serial port that another module can use for communication (e.g. mavlink).

# 示例

iridiumsbd <command> [arguments...]
 Commands:
   start
     -d <val>    Serial device
                 values: <file:dev>
     [-v]        Enable verbose output

   test
     [s|read|AT <cmd>] Test command

   stop

   status        print status info

# irlock

Source: drivers/irlock (opens new window)

# 使用

irlock <command> [arguments...]
 Commands:
   start
     [-I]        Internal I2C bus(es)
     [-X]        External I2C bus(es)
     [-b <val>]  board-specific bus (default=all) (external SPI: n-th bus
                 (default=1))
     [-f <val>]  bus frequency in kHz
     [-q]        quiet startup (no message if no device found)
     [-a <val>]  I2C address
                 default: 84

   stop

   status        print status info

# linux_pwm_out

Source: drivers/linux_pwm_out (opens new window)

# 描述

Linux PWM output driver with board-specific backend implementation.

# Usage

linux_pwm_out <command> [arguments...]
 Commands:
   start

   stop

   status        print status info

# lsm303agr

Source: drivers/magnetometer/lsm303agr (opens new window)

# 使用

lsm303agr <command> [arguments...]
 Commands:
   start
     [-s]        Internal SPI bus(es)
     [-S]        External SPI bus(es)
     [-b <val>]  board-specific bus (default=all) (external SPI: n-th bus
                 (default=1))
     [-c <val>]  chip-select pin (for internal SPI) or index (for external SPI)
     [-m <val>]  SPI mode
     [-f <val>]  bus frequency in kHz
     [-q]        quiet startup (no message if no device found)
     [-R <val>]  Rotation
                 default: 0

   stop

   status        print status info

# newpixel

Source: drivers/lights/neopixel (opens new window)

# Description

This module is responsible for driving interfasing to the Neopixel Serial LED

# Examples

It is typically started with:

neopixel -n 8

To drive all available leds.

# Usage

newpixel <command> [arguments...]
 Commands:
   stop

   status        print status info

# paa3905

Source: drivers/optical_flow/paa3905 (opens new window)

# Usage

paa3905 <command> [arguments...]
 Commands:
   start
     [-s]        Internal SPI bus(es)
     [-S]        External SPI bus(es)
     [-b <val>]  board-specific bus (default=all) (external SPI: n-th bus
                 (default=1))
     [-c <val>]  chip-select pin (for internal SPI) or index (for external SPI)
     [-m <val>]  SPI mode
     [-f <val>]  bus frequency in kHz
     [-q]        quiet startup (no message if no device found)
     [-Y <val>]  custom yaw rotation (degrees)
                 default: 0

   stop

   status        print status info

# paw3902

Source: drivers/optical_flow/paw3902 (opens new window)

# Usage

paw3902 <command> [arguments...]
 Commands:
   start
     [-s]        Internal SPI bus(es)
     [-S]        External SPI bus(es)
     [-b <val>]  board-specific bus (default=all) (external SPI: n-th bus
                 (default=1))
     [-c <val>]  chip-select pin (for internal SPI) or index (for external SPI)
     [-m <val>]  SPI mode
     [-f <val>]  bus frequency in kHz
     [-q]        quiet startup (no message if no device found)
     [-Y <val>]  custom yaw rotation (degrees)
                 default: 0

   stop

   status        print status info

# pca9685

Source: drivers/pca9685 (opens new window)

# Usage

pca9685 <command> [arguments...]
 Commands:
   start
     [-I]        Internal I2C bus(es)
     [-X]        External I2C bus(es)
     [-b <val>]  board-specific bus (default=all) (external SPI: n-th bus
                 (default=1))
     [-f <val>]  bus frequency in kHz
     [-q]        quiet startup (no message if no device found)
     [-a <val>]  I2C address
                 default: 64

   reset

   test          enter test mode

   stop

   status        print status info

# pca9685_pwm_out

Source: drivers/pca9685_pwm_out (opens new window)

# Description

This module is responsible for generate pwm pulse with PCA9685 chip.

It listens on the actuator_controls topics, does the mixing and writes the PWM outputs.

# Implementation

This module depends on ModuleBase and OutputModuleInterface. IIC communication is based on CDev::I2C

# Examples

It is typically started with:

pca9685_pwm_out start -a 64 -b 1

Use the mixer command to load mixer files. mixer load /dev/pwm_outputX etc/mixers/quad_x.main.mix The number X can be acquired by executing pca9685_pwm_out status when this driver is running.

# Usage

pca9685_pwm_out <command> [arguments...]
 Commands:
   start         Start the task
     [-a <val>]  device address on this bus
                 default: 64
     [-b <val>]  bus that pca9685 is connected to
                 default: 1
     [-r <val>]  schedule rate limit
                 default: 400

   stop

   status        print status info

# pmw3901

Source: drivers/optical_flow/pmw3901 (opens new window)

# Usage

pmw3901 <command> [arguments...]
 Commands:
   start
     [-s]        Internal SPI bus(es)
     [-S]        External SPI bus(es)
     [-b <val>]  board-specific bus (default=all) (external SPI: n-th bus
                 (default=1))
     [-c <val>]  chip-select pin (for internal SPI) or index (for external SPI)
     [-m <val>]  SPI mode
     [-f <val>]  bus frequency in kHz
     [-q]        quiet startup (no message if no device found)
     [-R <val>]  Rotation
                 default: 0

   stop

   status        print status info

# pps_capture

Source: drivers/pps_capture (opens new window)

# Description

This implements capturing PPS information from the GNSS module and calculates the drift between PPS and Real-time clock.

# Usage

pps_capture <command> [arguments...]
 Commands:
   start

   stop

   status        print status info

# pwm_out

Source: drivers/pwm_out (opens new window)

# Description

This module is responsible for driving the output pins. For boards without a separate IO chip (eg. Pixracer), it uses the main channels. On boards with an IO chip (eg. Pixhawk), it uses the AUX channels, and the px4io driver is used for main ones.

It listens on the actuator_controls topics, does the mixing and writes the PWM outputs.

On startup, the module tries to occupy all available pins for PWM/Oneshot output. It skips all pins already in use (e.g. by a camera trigger module).

# Implementation

By default the module runs on a work queue with a callback on the uORB actuator_controls topic.

# Usage

pwm_out <command> [arguments...]
 Commands:
   start

   stop

   status        print status info

# pwm_out_sim

Source: drivers/pwm_out_sim (opens new window)

# Description

Driver for simulated PWM outputs.

Its only function is to take actuator_control uORB messages, mix them with any loaded mixer and output the result to the actuator_output uORB topic.

It is used in SITL and HITL.

# Usage

pwm_out_sim <command> [arguments...]
 Commands:
   start         Start the module
     [-m <val>]  Mode
                 values: hil|sim, default: sim

   stop

   status        print status info

# px4flow

Source: drivers/optical_flow/px4flow (opens new window)

# Usage

px4flow <command> [arguments...]
 Commands:
   start
     [-I]        Internal I2C bus(es)
     [-X]        External I2C bus(es)
     [-b <val>]  board-specific bus (default=all) (external SPI: n-th bus
                 (default=1))
     [-f <val>]  bus frequency in kHz
     [-q]        quiet startup (no message if no device found)
     [-a <val>]  I2C address
                 default: 66

   stop

   status        print status info

# px4io

Source: drivers/px4io (opens new window)

# Description

Output driver communicating with the IO co-processor.

# Usage

px4io <command> [arguments...]
 Commands:
   start

   checkcrc      Check CRC for a firmware file against current code on IO
     <filename>  Firmware file

   update        Update IO firmware
     [<filename>] Firmware file

   debug         set IO debug level
     <debug_level> 0=disabled, 9=max verbosity

   bind          DSM bind
     dsm2|dsmx|dsmx8 protocol

   sbus1_out     enable sbus1 out

   sbus2_out     enable sbus2 out

   test_fmu_fail test: turn off IO updates

   test_fmu_ok   re-enable IO updates

   stop

   status        print status info

# rc_input

Source: drivers/rc_input (opens new window)

# Description

This module does the RC input parsing and auto-selecting the method. Supported methods are:

  • PPM
  • SBUS
  • DSM
  • SUMD
  • ST24
  • TBS Crossfire (CRSF)

# Usage

rc_input <command> [arguments...]
 Commands:
   start
     [-d <val>]  RC device
                 values: <file:dev>, default: /dev/ttyS3

   bind          Send a DSM bind command (module must be running)

   stop

   status        print status info

# rgbled

Source: drivers/lights/rgbled_ncp5623c (opens new window)

# Usage

rgbled <command> [arguments...]
 Commands:
   start
     [-I]        Internal I2C bus(es)
     [-X]        External I2C bus(es)
     [-b <val>]  board-specific bus (default=all) (external SPI: n-th bus
                 (default=1))
     [-f <val>]  bus frequency in kHz
     [-q]        quiet startup (no message if no device found)
     [-a <val>]  I2C address
                 default: 57
     [-o <val>]  RGB PWM Assignment
                 default: 123

   stop

   status        print status info

# roboclaw

Source: drivers/roboclaw (opens new window)

# Description

This driver communicates over UART with the Roboclaw motor driver (opens new window). It performs two tasks:

  • Control the motors based on the actuator_controls_0 UOrb topic.
  • Read the wheel encoders and publish the raw data in the wheel_encoders UOrb topic

In order to use this driver, the Roboclaw should be put into Packet Serial mode (see the linked documentation), and your flight controller's UART port should be connected to the Roboclaw as shown in the documentation. For Pixhawk 4, use the UART & I2C B port, which corresponds to /dev/ttyS3.

# Implementation

The main loop of this module (Located in RoboClaw.cpp::task_main()) performs 2 tasks:

  1. Write actuator_controls_0 messages to the Roboclaw as they become available
  2. Read encoder data from the Roboclaw at a constant, fixed rate.

Because of the latency of UART, this driver does not write every single actuator_controls_0 message to the Roboclaw immediately. Instead, it is rate limited based on the parameter RBCLW_WRITE_PER.

On startup, this driver will attempt to read the status of the Roboclaw to verify that it is connected. If this fails, the driver terminates immediately.

# Examples

The command to start this driver is:

$ roboclaw start

<device> is the name of the UART port. On the Pixhawk 4, this is /dev/ttyS3. <baud> is te baud rate.

All available commands are:

  • $ roboclaw start <device> <baud>
  • $ roboclaw status
  • $ roboclaw stop

# 描述

roboclaw <command> [arguments...]
 Commands:

# safety_button

Source: drivers/safety_button (opens new window)

# Description

This module is responsible for the safety button. Pressing the safety button 3 times quickly will trigger a GCS pairing request.

# Usage

safety_button <command> [arguments...]
 Commands:
   start

   stop

   status        print status info

# sht3x

Source: drivers/hygrometer/sht3x (opens new window)

# Description

SHT3x Temperature and Humidity Sensor Driver by Senserion.

# Examples

CLI usage example:

sht3x start -X

Start the sensor driver on the external bus

sht3x status

Print driver status

sht3x values

Print last measured values

sht3x reset

Reinitialize senzor, reset flags

# Usage

sht3x <command> [arguments...]
 Commands:
   start
     [-I]        Internal I2C bus(es)
     [-X]        External I2C bus(es)
     [-b <val>]  board-specific bus (default=all) (external SPI: n-th bus
                 (default=1))
     [-f <val>]  bus frequency in kHz
     [-q]        quiet startup (no message if no device found)
     [-a <val>]  I2C address
                 default: 68
     [-k]        if initialization (probing) fails, keep retrying periodically

   stop

   status        print status info

   values        Print actual data

   reset         Reinitialize sensor

# tap_esc

Source: drivers/tap_esc (opens new window)

# Description

This module controls the TAP_ESC hardware via UART. It listens on the actuator_controls topics, does the mixing and writes the PWM outputs.

# Implementation

Currently the module is implementd as a threaded version only, meaning that it runs in its own thread instead of on the work queue.

# Example

The module is typically started with: tap_esc start -d /dev/ttyS2 -n <1-8>

# Usage

tap_esc <command> [arguments...]
 Commands:
   start         Start the task
     [-d <val>]  Device used to talk to ESCs
                 values: <device>
     [-n <val>]  Number of ESCs
                 default: 4

# tone_alarm

Source: drivers/tone_alarm (opens new window)

# Description

This module is responsible for the tone alarm.

# Usage

tone_alarm <command> [arguments...]
 Commands:
   start

   stop

   status        print status info

# uwb

Source: drivers/uwb/uwb_sr150 (opens new window)

# Description

Driver for NXP UWB_SR150 UWB positioning system. This driver publishes a uwb_distance message whenever the UWB_SR150 has a position measurement available.

# Example

Start the driver with a given device:

uwb start -d /dev/ttyS2

# Usage

uwb <command> [arguments...]
 Commands:
   start
     -d <val>    Name of device for serial communication with UWB
                 values: <file:dev>
     -b <val>    Baudrate for serial communication
                 values: <int>
     -p <val>    Position Debug: displays errors in Multilateration
                 values: <int>

   stop

   status

# voxlpm

Source: drivers/power_monitor/voxlpm (opens new window)

# Usage

voxlpm [arguments...]
   start
     [-I]        Internal I2C bus(es)
     [-X]        External I2C bus(es)
     [-b <val>]  board-specific bus (default=all) (external SPI: n-th bus
                 (default=1))
     [-f <val>]  bus frequency in kHz
     [-q]        quiet startup (no message if no device found)
     [-a <val>]  I2C address
                 default: 68
     [-T <val>]  Type
                 values: VBATT|P5VDC|P12VDC, default: VBATT
     [-k]        if initialization (probing) fails, keep retrying periodically

   stop

   status        print status info