ardupilot/libraries/AP_HAL_Linux/RCOutput_AioPRU.h

// This program is free software: you can redistribute it and/or modify
// it under the terms of the GNU General Public License as published by
// the Free Software Foundation, either version 3 of the License, or
// (at your option) any later version.
// This program is distributed in the hope that it will be useful,
// but WITHOUT ANY WARRANTY; without even the implied warranty of
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
// GNU General Public License for more details.
// You should have received a copy of the GNU General Public License
// along with this program. If not, see <http://www.gnu.org/licenses/>.
#pragma once

#include "AP_HAL_Linux.h"
#define RCOUT_PRUSS_RAM_BASE 0x4a302000
#define RCOUT_PRUSS_CTRL_BASE 0x4a324000
#define RCOUT_PRUSS_IRAM_BASE 0x4a338000
#define PWM_CHAN_COUNT 12

class Linux::RCOutput_AioPRU : public AP_HAL::RCOutput {
    void     init();
    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);
    uint16_t read(uint8_t ch);
    void     read(uint16_t* period_us, uint8_t len);

private:
   static const uint32_t TICK_PER_US = 200;
   static const uint32_t TICK_PER_S = 200000000;

   struct pwm {
      volatile uint32_t channelenable;
      struct {
        volatile uint32_t time_high;
        volatile uint32_t time_t;
        } channel[PWM_CHAN_COUNT];
    };

    volatile struct pwm *pwm;
};