text: 
  #ifndef __AP_HAL_LINUX_RCOUTPUT_PCA9685_H__
  #define __AP_HAL_LINUX_RCOUTPUT_PCA9685_H__
  
  #include "AP_HAL_Linux.h"
  
  #define PCA9685_PRIMARY_ADDRESS             0x40 // All address pins low, PCA9685 default
  #define PCA9685_SECONDARY_ADDRESS           0x41
  #define PCA9685_TERTIARY_ADDRESS            0x42
  
  class Linux::RCOutput_PCA9685 : public AP_HAL::RCOutput {
      public:
      RCOutput_PCA9685(uint8_t addr, bool external_clock, uint8_t channel_offset,
                            int16_t oe_pin_number);
      ~RCOutput_PCA9685();
      void     init(void* machtnichts);
      void     reset_all_channels();
      void     set_freq(uint32_t chmask, uint16_t freq_hz);
      uint16_t get_freq(uint8_t ch);
      void     enable_ch(uint8_t ch);
      void     disable_ch(uint8_t ch);
      void     write(uint8_t ch, uint16_t period_us);
      void     cork() override;
      void     push() override;
      uint16_t read(uint8_t ch);
      void     read(uint16_t* period_us, uint8_t len);
  
  private:
      void reset();
  
      AP_HAL::Semaphore *_i2c_sem;
      AP_HAL::DigitalSource *_enable_pin;
      uint16_t _frequency;
      float _osc_clock;
  
      uint16_t *_pulses_buffer;
  
      uint8_t _addr;
      bool _external_clock;
      bool _corking = false;
      uint8_t _channel_offset;
      int16_t _oe_pin_number;
      uint16_t _pending_write_mask;
  };
  
  #endif // __AP_HAL_LINUX_RCOUTPUT_PCA9685_H__
  