ardupilot/libraries/AP_HAL/RCOutput.h

#ifndef __AP_HAL_RC_OUTPUT_H__
#define __AP_HAL_RC_OUTPUT_H__

#include "AP_HAL_Namespace.h"

/* Define the CH_n names, indexed from 1, if we don't have them already */
#ifndef CH_1
#define CH_1 0
#define CH_2 1
#define CH_3 2
#define CH_4 3
#define CH_5 4
#define CH_6 5
#define CH_7 6
#define CH_8 7
#define CH_9 8
#define CH_10 9
#define CH_11 10
#define CH_12 11
#define CH_13 12
#define CH_14 13
#define CH_15 14
#define CH_16 15
#define CH_17 16
#define CH_18 17
#endif


class AP_HAL::RCOutput {
public:
    virtual void init(void* implspecific) = 0;

    /* Output freq (1/period) control */
    virtual void     set_freq(uint32_t chmask, uint16_t freq_hz) = 0;
    virtual uint16_t get_freq(uint8_t ch) = 0;

    /* Output active/highZ control, either by single channel at a time
     * or a mask of channels */
    virtual void     enable_ch(uint8_t ch) = 0;
    virtual void     disable_ch(uint8_t ch) = 0;

    /* Output, either single channel or bulk array of channels */
    virtual void     write(uint8_t ch, uint16_t period_us) = 0;
    virtual void     write(uint8_t ch, uint16_t* period_us, uint8_t len) = 0;

    /* Read back current output state, as either single channel or
     * array of channels. */
    virtual uint16_t read(uint8_t ch) = 0;
    virtual void     read(uint16_t* period_us, uint8_t len) = 0;

    /*
      set PWM to send to a set of channels when the safety switch is
      in the safe state
     */
    virtual void     set_safety_pwm(uint32_t chmask, uint16_t period_us) {}

    /*
      set PWM to send to a set of channels if the FMU firmware dies
     */
    virtual void     set_failsafe_pwm(uint32_t chmask, uint16_t period_us) {}

    /*
      force the safety switch off, enabling PWM output from the IO board
     */
    virtual void     force_safety_off(void) {}
};

#endif // __AP_HAL_RC_OUTPUT_H__