#include                    "soc/rtc.h"

#define GPIO_pin 5

uint32_t Freq = 0;
uint32_t cpuSpeed;
rtc_cpu_freq_t                MyCPU_Freq;
rtc_xtal_freq_t               MyXTAL_Freq;
rtc_cpu_freq_config_t         MyCPUconfig;
boolean                   Answer1;

void setup()
{
  
  pinMode(GPIO_pin, OUTPUT);
  Serial.begin(115200);
  Serial.println(F("###############################"));
  rtc_clk_cpu_freq_get_config(&MyCPUconfig);
  cpuSpeed = getCpuFrequencyMhz();
  Serial.println(F("\t\t-- Sources of microcontroller frequency applied --"));
  Serial.print(F("\u2714 CPU speed in MHz is: "));
  Serial.println(cpuSpeed, DEC);
  Serial.print(F("\u2714 PLL Source clock frequency: "));
  Serial.println(MyCPUconfig.source_freq_mhz, DEC);
  Serial.print(F("\u2714 CPU clock frequency: "));
  Serial.println(MyCPUconfig.freq_mhz, DEC);
  Serial.print(F("\u2714 Division factor: "));
  Serial.println(MyCPUconfig.div, DEC);
  Serial.print(F("\u2714 Source clock frequency is: "));
  switch (MyCPUconfig.source) {
    case RTC_CPU_FREQ_SRC_XTAL:
      Serial.println(F("External oscillator"));
      break;
    case RTC_CPU_FREQ_SRC_PLL:
      Serial.println(F("Phase Locked Loop (480 MHz or 320 MHz)"));
      break;
    case RTC_CPU_FREQ_SRC_8M:
      Serial.println(F("Internal 8MHz RTC oscillator"));
      break;
    case RTC_CPU_FREQ_SRC_APLL:
      Serial.println(F("Audio PLL"));
      break;
  }
  Serial.println(F("-----------------------"));

  Freq=getCpuFrequencyMhz();
  Serial.print("CPU Freq = ");
  Serial.print(Freq);
  Serial.println("Mhz");
  Freq=getXtalFrequencyMhz();
  Serial.print("XTAL Freq = ");
  Serial.print(Freq);
  Serial.println(" Mhz");
  Freq = getApbFrequency();
  Serial.print("Apb Freq = ");
  Serial.print(Freq);
  Serial.println(" Hz");
  Serial.println(F("-----------------------"));
  setCpuFrequencyMhz(80);
  
  Serial.println(F("\t\t** Source of CPU frequency applied **"));
  if (MyCPUconfig.source != RTC_CPU_FREQ_SRC_XTAL) {
      MyCPUconfig.source = RTC_CPU_FREQ_SRC_XTAL;
      MyCPUconfig.div = 1;
      rtc_clk_cpu_freq_set_config(&MyCPUconfig);
      Serial.println(F("The source clock applied for frequency CPU is external oscillator now"));
      MyXTAL_Freq = rtc_clk_xtal_freq_get();
      Serial.print(F("\u2714 Value stored in RTC register RTC_XTAL_FREQ_REG: "));
      switch (MyXTAL_Freq) {
        case RTC_XTAL_FREQ_AUTO:
          Serial.println(F("Automatic XTAL frequency detection"));
          break;
        case RTC_XTAL_FREQ_40M:
          Serial.println(F("40 MHz XTAL"));
          break;
        case RTC_XTAL_FREQ_26M:
          Serial.println(F("26 MHz XTAL"));
          break;
        case RTC_XTAL_FREQ_24M:
          Serial.println(F("24 MHz XTAL"));
          break;
      }
      rtc_clk_cpu_freq_to_config(MyCPU_Freq, &MyCPUconfig);
      Serial.print(F("\u2714 RTC CPU frequency: "));
      switch (MyCPU_Freq)  {
        case RTC_CPU_FREQ_XTAL:
          Serial.println(F("Main XTAL frequency"));
          break;
        case RTC_CPU_FREQ_80M:
          Serial.println(F("CPU frequency is 80 MHz"));
          break;
        case RTC_CPU_FREQ_160M:
          Serial.println(F("CPU frequency is 160 MHz"));
          break;
        case RTC_CPU_FREQ_240M:
          Serial.println(F("CPU frequency is 240 MHz"));
          break;
        case RTC_CPU_FREQ_2M:
          Serial.println(F("CPU frequency is 2 MHz"));
          break;
      }

      rtc_clk_cpu_freq_get_config(&MyCPUconfig);
      cpuSpeed = getCpuFrequencyMhz();
      Answer1 = setCpuFrequencyMhz(80);
      if (Answer1 == true) Serial.println(F("CPU frequency has been changed"));
      Serial.print(F("\u2714 CPU speed in MHz is: "));
      Serial.println(cpuSpeed, DEC);
      Serial.print(F("\u2714 PLL Source clock frequency: "));
      Serial.println(MyCPUconfig.source_freq_mhz, DEC);
      Serial.print(F("\u2714 CPU clock frequency: "));
      Serial.print(MyCPUconfig.freq_mhz, DEC);
      Serial.println(F(" MHz"));
      Serial.print(F("\u2714 Divider applied: "));
      Serial.print(MyCPUconfig.div, DEC);


  }
}

void loop()
{
  digitalWrite(GPIO_pin, 1);
  digitalWrite(GPIO_pin, 0);
}