HardwareGPIO_FTDI.h

#pragma once
/*
  HardwareGPIO_FTDI.h 
  Copyright (c) 2025 Phil Schatzmann. All right reserved.
 
  This library is free software; you can redistribute it and/or
  modify it under the terms of the GNU Lesser General Public
  License as published by the Free Software Foundation; either
  version 2.1 of the License, or (at your option) any later version.
 
  This library 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
  Lesser General Public License for more details.
 
  You should have received a copy of the GNU Lesser General Public
  License along with this library; if not, write to the Free Software
  Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA
*/
#ifdef USE_FTDI
#include <ftdi.h>
// Undefine DEPRECATED macro from libftdi1 to avoid conflict with Arduino API
#ifdef DEPRECATED
#undef DEPRECATED
#endif
#include "HardwareGPIO.h"
#include <map>
#include <thread>
#include <atomic>
#include <mutex>
#include <chrono>
 
namespace arduino {
 
class HardwareGPIO_FTDI : public HardwareGPIO {
 public:
  HardwareGPIO_FTDI() = default;
 
  ~HardwareGPIO_FTDI();
 
  bool begin(int vendor_id = 0x0403, int product_id = 0x6010, 
            const char* description = nullptr, const char* serial = nullptr);
 
  void end();
 
  void pinMode(pin_size_t pinNumber, PinMode pinMode) override;
 
  void digitalWrite(pin_size_t pinNumber, PinStatus status) override;
 
  PinStatus digitalRead(pin_size_t pinNumber) override;
 
  int analogRead(pin_size_t pinNumber) override;
 
  void analogReference(uint8_t mode) override;
 
  void analogWrite(pin_size_t pinNumber, int value) override;
 
  void analogWriteFrequency(pin_size_t pinNumber, uint32_t frequency);
 
  void tone(uint8_t _pin, unsigned int frequency,
            unsigned long duration = 0) override;
 
  void noTone(uint8_t _pin) override;
 
  unsigned long pulseIn(uint8_t pin, uint8_t state,
                        unsigned long timeout = 1000000L) override;
 
  unsigned long pulseInLong(uint8_t pin, uint8_t state,
                            unsigned long timeout = 1000000L) override;
 
  void analogWriteResolution(uint8_t bits) override;
 
  operator bool() { return is_open && ftdi_context != nullptr; }
 
  void getPWMStatistics(pin_size_t pin, uint64_t& cycles, 
                       uint64_t& max_jitter_us, uint64_t& avg_jitter_us);
 
 protected:
  struct ftdi_context* ftdi_context = nullptr;
  bool is_open = false;
  
  // Pin state tracking
  uint8_t pin_directions_a = 0x00;  // Channel A direction mask (1=output, 0=input)
  uint8_t pin_values_a = 0x00;      // Channel A output values
  uint8_t pin_directions_b = 0x00;  // Channel B direction mask
  uint8_t pin_values_b = 0x00;      // Channel B output values
  
  // Pin mode tracking
  std::map<pin_size_t, PinMode> pin_modes;
  
  // PWM state tracking
  struct PWMPin {
    bool enabled = false;
    uint8_t duty_cycle = 0;     // 0-255
    uint32_t frequency = 1000;  // Hz
    uint32_t period_us = 1000;  // Period in microseconds
    uint32_t on_time_us = 0;    // On time in microseconds
    std::chrono::high_resolution_clock::time_point period_start;  // Start of current period
    bool current_state = false;
    uint64_t cycle_count = 0;   // Total cycles for drift correction
    // Statistics for monitoring
    uint64_t max_jitter_us = 0;
    uint64_t total_jitter_us = 0;
  };
  
  std::map<pin_size_t, PWMPin> pwm_pins;
  std::thread pwm_thread;
  std::atomic<bool> pwm_thread_running{false};
  std::mutex pwm_mutex;
 
  bool updateGPIOState(int channel);
 
  bool readGPIOState(int channel, uint8_t& value);
 
  int getChannel(pin_size_t pin) { return (pin >= 8) ? 1 : 0; }
 
  int getBitPosition(pin_size_t pin) { return pin % 8; }
  
  void pwmThreadFunction();
  
  void startPWMThread();
  
  void stopPWMThread();
  
  void updatePWMPin(pin_size_t pin, uint8_t duty_cycle, uint32_t frequency = 1000);
};
 
}  // namespace arduino
 
#endif  // USE_FTDI