#include "stdio.h"                                                        // Library STDIO
#include "driver/ledc.h"                                                  // Library ESP32 LEDC
#include "driver/pcnt.h"                                                  // Library ESP32 PCNT
#include "driver/gpio.h"
#include "soc/pcnt_struct.h"
#include "freertos/FreeRTOS.h"



void setup() {
  // put your setup code here, to run once:
  Serial.begin(115200);
  Serial.println("Hello, ESP32-S3!");
  uint32_t f = getCpuFrequencyMhz();
  Serial.println(f);
  init_osc_freq();
  init_PCNT();
  init_GPIO();
}

uint32_t multPulses = 0;
int16_t pulses = 0; 
float frequency = 0.0f;
bool low_signal_periode_begin = false;

void loop() {
 if (low_signal_periode_begin) {
  low_signal_periode_begin = false;
  low_periode_triggered();
  // printf( "frequency %f\n", frequency );
 }
 
}


void init_osc_freq ()                                                     // Initialize Oscillator to test Freq Meter
{
  ledc_timer_config_t ledc_timer = {};                                    // LEDC timer config instance


  ledc_timer.duty_resolution =  LEDC_TIMER_1_BIT;                         // Set resolution
  ledc_timer.freq_hz    = 8000000;                                        // Set Oscillator frequency
  ledc_timer.speed_mode = LEDC_LOW_SPEED_MODE;                            // Set low speed mode ESP32-S3
  ledc_timer.timer_num = LEDC_TIMER_0;                                    // Set LEDC timer index - 0
  ledc_timer.clk_cfg = LEDC_AUTO_CLK;                                  
  ledc_timer_config(&ledc_timer);                                         // Set LEDC Timer config

  ledc_channel_config_t ledc_channel = {};                                // LEDC Channel config instance

  ledc_channel.channel    = LEDC_CHANNEL_0;                               // Set HS Channel - 0
  ledc_channel.duty       = 1;                                            // Set Duty Cycle 50%
  ledc_channel.gpio_num   = 4;                                            // LEDC Oscillator output GPIO 33
  ledc_channel.intr_type  = LEDC_INTR_DISABLE;                            // LEDC Fade interrupt disable
  ledc_channel.speed_mode = LEDC_LOW_SPEED_MODE;                          // Set LEDC high speed mode
  ledc_channel.timer_sel  = LEDC_TIMER_0;                                 // Set timer source of channel - 0
  ledc_channel_config(&ledc_channel);                                     // Config LEDC channel
}

portMUX_TYPE timerMux = portMUX_INITIALIZER_UNLOCKED;  
     

//----------------------------------------------------------------------------------
static void IRAM_ATTR pcnt_intrrupt_handler(void *arg)                        // Counting overflow pulses
{
  portENTER_CRITICAL_ISR(&timerMux);                                      // disabling the interrupts
  multPulses++;                                                           // increment Overflow counter
  PCNT.int_clr.val = BIT(PCNT_UNIT_0);                                    // Clear Pulse Counter interrupt bit
  portEXIT_CRITICAL_ISR(&timerMux);                                       // enabling the interrupts
  printf( "E\n");
}

//----------------------------------------------------------------------------------
void init_PCNT(void)                                                      // Initialize and run PCNT unit
{
  pcnt_config_t pcnt_config = { };                                        // PCNT unit instance

  pcnt_config.pulse_gpio_num = GPIO_NUM_5;                                         // Pulse input GPIO 5 LEDC
  pcnt_config.ctrl_gpio_num = GPIO_NUM_6;                                          // Control signal input GPIO 6
  pcnt_config.unit = PCNT_UNIT_0;                                         //
  pcnt_config.channel = PCNT_CHANNEL_0;                                   // PCNT unit number - 0
  pcnt_config.counter_h_lim = 20000;                                      // Maximum counter value - 20000
  pcnt_config.pos_mode = PCNT_COUNT_INC;                                  // PCNT positive edge count mode - inc
  pcnt_config.neg_mode = PCNT_COUNT_INC;                                  // PCNT negative edge count mode - inc
  pcnt_config.lctrl_mode = PCNT_MODE_DISABLE;                             // PCNT low control mode - disable
  pcnt_config.hctrl_mode = PCNT_MODE_KEEP;                                // PCNT high control mode - won't change counter mode
  esp_err_t error = pcnt_unit_config(&pcnt_config);                       // Initialize PCNT unit
   if (error = ESP_ERR_INVALID_STATE) 
  {
    printf( "ESP_ERR_INVALID_STATE\n");
  }

  pcnt_counter_pause(PCNT_UNIT_0);                                        // Pause PCNT unit
  pcnt_counter_clear(PCNT_UNIT_0);                                        // Clear PCNT unit

  pcnt_event_enable(PCNT_UNIT_0, PCNT_EVT_H_LIM);                         // Enable event to watch - max count
  pcnt_isr_register(pcnt_intrrupt_handler, NULL, 0, NULL);                // Setup Register ISR handler
  pcnt_intr_enable(PCNT_UNIT_0);                                          // Enable interrupts for PCNT unit
  pcnt_counter_resume(PCNT_UNIT_0);                                       // Resume PCNT unit - starts count
}


void low_periode_triggered( void )
{
  esp_err_t error = pcnt_get_counter_value(PCNT_UNIT_0, &pulses);   
  if (error = ESP_ERR_INVALID_STATE) 
  {
    // printf( "ESP_ERR_INVALID_STATE\n");
  }
  frequency = (pulses + (multPulses * 20000)) / 2;
}


static void IRAM_ATTR gpio_isr_handler_gpio7(void* arg)
{
  low_signal_periode_begin = true;
}



void init_GPIO() 
{
  gpio_num_t gpio_num = GPIO_NUM_7;

  gpio_install_isr_service(0);
  gpio_reset_pin(gpio_num);
  gpio_set_direction(gpio_num, GPIO_MODE_INPUT);
  gpio_pullup_en(gpio_num);
  gpio_set_intr_type(gpio_num, GPIO_INTR_POSEDGE);
  gpio_isr_handler_add(gpio_num, gpio_isr_handler_gpio7, NULL);
}